Category: Vaccine

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Vaccine-Preventable Diseases Surge: Europe Sounds the Alarm – Medscape

April 28, 2024

The latest data from the European Centre for Disease Prevention and Control (ECDC) reveal a concerning uptick in vaccine-preventable diseases such as measles and pertussis across Europe, following decreased levels throughout the COVID-19 pandemic period. The findings were released as part of the 2024 European Immunization Week, taking place April 21-27, and emphasize a critical need for heightened vaccination campaigns to protect public health.

After a period of low activity between 2020 and 2022, the number of measles cases began increasing in 2023, persisting across several EU member states. From March 2023 to February 2024, more than 5770 measles cases were reported, with at least five deaths.

Infants younger than 1 year face the highest risk owing to their inability to receive vaccinations, relying on immunity in the community for protection. Measles, known for its high transmissibility, necessitates that at least 95% of a population receive two doses of measles-containing vaccine to halt transmission.

A surge in pertussis cases also emerged in mid-2023 across various EU/EEA countries, with preliminary data indicating a more than 10-fold increase compared with 2022 and 2021. Newborns and infants, who are vulnerable owing to incomplete vaccination, face heightened risks for severe illness and mortality. Timely administration of all recommended pertussis-containing vaccines is imperative to safeguard this group, with vaccination during pregnancy offering additional protection for young infants.

"The measles and pertussis outbreaks are just two examples [showing] that, despite the dramatic decrease in cases and mortality over the past decades, different vaccine-preventable diseases continue to circulate and still inflict suffering in those unprotected or vulnerable," cautioned Andrea Ammon, director of the ECDC, during a press conference.

Mumps: Although considered minor, the uptick in mumps cases warrants attention. In 2022, 27 EU/EEA countries collectively reported 2593 cases of mumps, marking an increase in the overall notification rate from 0.4 to 0.7 case per 100,000 population compared with 2021.

Diphtheria: This disease remains rare in EU/EEA countries, yet 2022 saw a concerning rise with 359 reported cases, which were predominantly cutaneous diphtheria. Notably, more than 60% of diphtheria cases occurred in a country different from the one in which they were notified, indicating potential challenges in surveillance and response.

Invasive meningococcal disease: In 2022, a surge in invasive meningococcal disease was recorded across all EU/EEA countries, totaling 1149 confirmed cases and resulting in 110 deaths. This marks a stark increase from 2021, in which 612 cases and 48 deaths were reported.

As outbreaks of vaccine-preventable diseases persist across EU/EEA countries, concerted efforts are imperative to pinpoint immunity gaps within the population, particularly among individuals who may have missed or postponed their vaccinations. Action is required to ensure equitable access to vaccinations, particularly among vulnerable and marginalized groups such as refugees, migrants, and asylum seekers.

The ECDC reaffirmed its commitment to bolster national vaccination programs and to uphold vaccine quality, safety, and efficacy, while striving for universal and equitable access for all.

Ammon emphasized that EIW, which takes place across Europe every year in the final week of April, serves as an opportunity to reflect on the monumental impact vaccines have had and continue to have on people worldwide and their role in overall health and well-being across all age groups. The European Region of the World Health Organization has designated "Protecting Generations" as the theme of EIW 2024, commemorating 50 years of the Essential Programme on Immunization.

"Achieving and maintaining high vaccination uptake, disease surveillance, and prompt response actions to control outbreaks remain the key actions against these diseases. Vaccines have protected many generations, and we should ensure that this continues to be the case," Ammon said.

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Vaccine-Preventable Diseases Surge: Europe Sounds the Alarm - Medscape

Quality control in SARS-CoV-2 RBD-Fc vaccine production using LCMS to confirm strain selection and detect … – Nature.com

April 28, 2024

In vaccine production, QC is an important step to confirm identities of raw materials, relevant ingredients and final products. They are also screened for unwanted contaminants within the QC processes25,26. In case of SARS-CoV-2 vaccine production, the presence of other viral strains in the drug substances and/or end products would lead to failure of product tests and may cause a drop in efficacy and/or increase the risk of adverse events27. Therefore, establishing a suitable method for checking authenticity of the SARS-CoV-2 strain selected for vaccine production and detecting contaminants from other strains is essential for vaccine quality assessment. LCMS technique is widely known for its sensitivity, robustness, accuracy and high throughput28. It has a benefit over an enzyme-linked immunosorbent assay (ELISA) because it can detect several peptides from one or multiple viral strains in a single run29. LCMS method has been broadly used in clinical research to identify SARS-CoV-2 variants, but surprisingly its application in manufacturing process of biological products has less been found30. This study demonstrated that LCMS can be a useful tool for evaluating product quality in biopharmaceutical production.

Wuhan and early developed SAR-CoV-2 strains, for example Alpha, Beta, Gamma, Delta and Epsilon show little variation among their RBD amino acid sequences, demonstrating their close relationships. However, more recently emerging Omicron strains show 17 amino acids different from Wuhan wild type, indicating substantial evolution of Omicron lineages (Fig.1). All distinct amino acids detected among 14 SARS-CoV-2 strains contribute to nine characteristic peptides upon tryptic digestion. Most of the characteristic peptides can be readily detected in LCMS analysis but unmodified peptide 6 is hardly detected. The sequence between 150D and 192R positions (43 amino acids in length) has neither arginine (R) nor lysine (K), digestive sites of trypsin enzyme, causing a lengthy peptide after digestion. The large peptide could become low hydrophilicity, poor ionization, limited fragmentation and could comprise multiple charge states, resulting in low or no signal in LCMS analysis31,32. In the RBD-Fc sequences of different SARS-CoV-2 strains, including Delta, Iota, Theta and Eta strains, T161 or E167 position is substituted with K, yielding digestible peptides, which are useful for differentiating these strains from the others and from each other (Fig.3). Peptides 1, 2, 3, 4 and 7 are applicable for detecting Omicron BA1 and BA2. Peptide 3 is helpful for identifying Beta and Gamma strains. Peptides 8 and 9 are required for identifying Zeta and Alpha strains, respectively. Peptide 5 is unique for Lambda strain and applicable for distinguishing Kappa and Epsilon strains from the others. When all characteristic peptides were used together (Fig.3) and the identification processes were followed step by step from the top to the bottom, identification of SAR-CoV-2 strains can be achieved in a single attempt, even from a mix of recombinant RBD-Fc proteins derived from different viral strains (Fig.4).

However, Kappa and Epsilon strains cannot be differentiated from each other with this LCMS method because they have only one amino-acid difference, which does not contribute to a characteristic peptide after tryptic digestion. To overcome this issue, GluC protease could be an alternative enzyme for using alone or together with trypsin enzyme to additionally cleave the proteins at C-terminus of glutamic acid (E). GluC enzyme could facilitate the differentiation of SARS-CoV-2 RBD-Fc proteins derived from Epsilon and Kappa strain because the sequence of Epsilon strain contains glutamic acid at position 167 (E167), which is cleavable by GluC enzyme. However, this amino acid is mutated to glutamine (Q167) for Kappa strain. After GluC digestion, the resulting peptides would be different between the samples derived from Epsilon and Kappa strains and therefore distinguishable by LCMS analysis. Apart from GluC enzyme, other proteases, such as LysC, ArgC and AspN enzymes, could be additionally applied to increase completeness of protein digestion at lysine (K) and arginine (R) positions or additionally cleave the peptide at aspartic acid (D) position to increase number of resulting peptides. This could lead to better detection and differentiation of vaccine products derived from closely related SARS-CoV-2 strains. However, time and cost would be factors of concern as increased number of enzymes will double digestion time and chemical use.

Post-translational modifications of N-glycosylation could be another factor, affecting LCMS results and analytical performance to confirm protein identity and detect contaminations. In this study, characteristic peptide 1 has one glycosylation site at N26 amino acid. Sometimes, MS/MS signal of the non-glycosylated form was not observed. Peptide 1 is important for differentiating RBD-Fc proteins derived from Omicron BA1 and BA2 from the others. To improve the MS/MS signal of peptide 1 and abate the effects of N-glycosylation, protease enzymes, such as Endo-S and PNGase A, could be additionally used to release N-glycans from the core protein structure. Nonetheless, other characteristic peptides, including peptides 2, 3, 4 and 7, are appliable for distinguishing Omicron BA1 and BA2 strains from each other and from the others. Hence, Endo-S and PNGase A enzymes might not be necessary in this study, but they would benefit the other studies, discovering that only N-glycosylated peptide is a characteristic peptide.

In typical LCMS analysis, the resulting peptides are matched to the reference sequence of individual proteins. For example, the result from Wuhan SARS-CoV-2 RBD-Fc sample is usually compared against the reference amino acid sequence of Wuhan strain only (Fig.2). Identity of Wuhan strain might be confirmed but potential contaminants from other strains would not be identified. By having the peptide key alongside the reference of target protein, purity of intermediate substances and vaccine products can be more ascertained. Generally, the limit of LCMS detection is in a range of 110ngml1 solution or ng mg1 protein33,34. Within this study, a protein spike-in assay was performed to examine the limits of peptide detection. Among nine characteristic peptides, the lowest points of peptide detection at MS/MS level were around 5ngml1, observed from peptide 5 and 8 (Table 1). These two peptides are unique for detecting RBD-Fc derived from Lambda, Zeta, Epsilon or Kappa strains. Peptide 3 for detecting RBD-Fc derived Gamma strain and peptide 6.1 for detecting RBD-Fc derived from Iota strain were detectable at concentration around 20ngml1, demonstrating relatively sensitive detection by this developed LCMS method. Detection limits of other peptides were in a range of 50200ngml1, which would be sufficient for detecting even small contaminations in our vaccine production. Contaminants from other strains likely occur at microgram level since the tested materials are typically prepared at 1mgml1.

According to the WHO guideline, cross-contamination of biological materials at any stage during biopharmaceutical manufacturing is a risk and must be assessed and controlled19. In our production system, biological materials can be derived from different SARS-CoV-2 strains, therefore appropriate logistic plans and activities, such as a clear separation of storage areas between different bacteria cell banks and avoiding infiltrating different strains at the same time, must be exercised to reduce the risk. These processes have already been implemented in the manufacturing plant of Baiya Phytopharm. An implementation of LCMS analysis in the QC process will ensure the purity of starting materials and final vaccine products. Furthermore, molecular techniques, such as real-time PCR, could be further developed to check contaminations of different SARS-CoV-2 strains in bacterial clones and DNA plasmids during cloning and transformation steps. It could also be used to track down microbial contaminations and host cell DNA residues in the final vaccine products35. By using bioanalytical and molecular techniques in combination, QC analysis in biologic manufacture would be more forceful to ensure production integrity and product quality.

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Quality control in SARS-CoV-2 RBD-Fc vaccine production using LCMS to confirm strain selection and detect ... - Nature.com

The path to a better tuberculosis vaccine runs through Montana – Bozeman Daily Chronicle

April 28, 2024

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The path to a better tuberculosis vaccine runs through Montana - Bozeman Daily Chronicle

New data shows vaccines have saved 154 million lives in the past 50 years – Gavi, the Vaccine Alliance

April 28, 2024

Vaccines are the most effective way of preventing infectious disease and saving lives.

The Expanded Programme on Immunization (EPI), launched by the World Health Organization in 1974 in response to high rates of vaccine-preventable disease worldwide, was a significant milestone in public health. By reaching communities around the world with life-saving vaccines, the programme has contributed to an enormous reduction in preventable diseases.

The EPI helped eliminate smallpox, fight polio and massively reduce child mortality. After 50 years of its existence, an analysis published in The Lancet today show just how far-reaching the impact of the programme has been. This framework estimates deaths averted, years of life saved and years of full health gained for 14 pathogens within the EPI portfolio.

The analysis builds upon infectious disease modelling estimates produced by the Vaccine Impact Modelling Consortium (VIMC) and the Global Burden of Disease study (GBD).

Here are five key achievements.

Between 1974 and 2024, 40% of the global reduction in infant mortality is attributable to vaccination (this benefit goes up to 52% in Africa). Improvements in water, sanitation and hygiene, better nutrition and other factors have improved health and reduced the spread of disease since the 1970s, but vaccination has made the biggest single contribution to the prevention of deadly infections.

Where vaccines have been able to stop transmission, vaccination of a critical number of people has protected unvaccinated people too which is referred to as herd immunity.

Measles is highly contagious one infected person can spread the virus to 18 other people. Not only can it be fatal, but it can cause lifelong disability in the form of blindness, deafness or intellectual disability.

Over 50 years, vaccines have prevented nearly 94 million deaths from measles and saved 5.7 billion years of life. However there remain challenges in getting measles vaccines out to all those who need them according to WHO, 22 million children missed their routine first dose of measles vaccine in 2022, compared to 19 million in 2019.

The majority of lives saved are in children younger than five years old. More than 9 billion years of life have been saved since 1974.

Young children are the most vulnerable to many of the diseases that can be prevented by vaccines. Many of the diseases prevented by the EPI, such as rubella, polio, pertussis, pneumococcal disease and rotavirus, disproportionately affect young children.

The benefits to older adults are greatest in African and Eastern Mediterranean regions, however people worldwide are still seeing the benefits of vaccination even at age 50.

Vaccination doesn't just save lives, it also prevents the long-term consequences associated with severe disease, especially polio.

For every life saved, 66 years of full health were gained on average, translating to 10.2 billion years of full health gained. This takes into account years of disability caused by disease.

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New data shows vaccines have saved 154 million lives in the past 50 years - Gavi, the Vaccine Alliance

Longhorn Vaccines and Diagnostics Presents New Data on its Best-In-Class Infectious Disease Vaccine and Antibody … – Yahoo Finance

April 28, 2024

LHNVD-105, a universal influenza vaccine, shows strong immunogenicity at low doses in pigs, validating previous studies in rodents

Monoclonal antibodies generated by LHNVD-105 demonstrates the need for targeting multiple different conserved regions on the influenza virus

LHNVD-301, a monoclonal antibody cocktail targeting the heat shock protein, demonstrates strong activity against clinical tuberculosis isolates

BETHESDA, Md. & GAITHERSBURG, Md., April 27, 2024--(BUSINESS WIRE)--Longhorn Vaccines and Diagnostics, a One Health company developing vaccines and diagnostic tools for global public health and zoonosis concerns, presented positive data from three key studies of its infectious disease franchise at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) 2024. ECCMID is taking place online and in-person in Barcelona, Spain from April 27-30, 2024.

Longhorns vaccine and antibody product candidates focus on rapidly mutating viruses that include influenza, coronavirus, and antimicrobial resistant pathogens. The candidates presented include LHNVD-105, an adjuvanted composite peptide vaccine that targets multiple stages of the viral replication process, and a monoclonal antibody cocktail that targets a protein that may play a significant role in allowing tuberculosis to remain in a latent stage.

Influenza is a prevalent zoonotic respiratory virus, with pigs acting as a middleman for generating new virus strains transferrable to humans, birds, and other swine with pandemic potential. This poses a major public health issue and challenges to the swine industry. The first of two studies on LHNVD-105, Longhorns universal influenza vaccine, showcased how unconjugated multi-epitope peptides, formulated with AddaVaxTM adjuvant, generated antibodies that were broadly reactive across multiple influenza virus strains when administered to pigs at low doses. Results included:

Pigs immunized with LHNVD-105 generated IgG antibodies that bound to multiple strains of influenza virus 21 days post primary immunization after a single dose.

Pigs receiving low vaccine doses (1 and 5g) generated binding antibodies to influenza viruses equal to or higher than pigs in the high dose groups (50 and 100g).

No adverse reactions to the vaccine were observed.

"We are very excited to present the first data from our universal influenza vaccine in pigs," said Jeff Fischer, President Longhorn Vaccines and Diagnostics. "Pigs are an ideal model for influenza and the results mirrored the significant rodent data that has been previously published."

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Seasonal circulation of rapidly evolving influenza strains are potential threats in human populations. For individuals with increased risk of exposure to influenza or immunocompromised, new strains resistant to antiviral therapies pose a life-threatening risk. The second study on LHNVD-105 evaluated the binding and functional capabilities of four different isotype-specific anti-influenza mAbs in mice to determine their candidacy for a cocktail therapy approach to influenza. Results demonstrated:

Anti-influenza mAbs LD9 (IgG1, anti-HA), NB5 (IgG2a, anti-NA), GA4 (IgG1, anti-Matrix), and CG6, (IgG3, anti-Matrix) bound equally well to H3N2, but differentially to other contemporary and pandemic strains.

Anti-HA mAb LD9 and anti-Matrix mAb GA4 (both IgG1) preferentially bound to pandemic H5N1 influenza strain, while anti-Matrix mAb CG6 was more reactive with influenza B.

Anti-NA mAb NB5 and anti-Matrix mAb CG6 both had higher affinities to H3N2 and influenza B, but reacted less well to H1N1 and H5N1.

Neutralizing activity of all four mAbs was demonstrated against H1N1 and H3N2.

"Tuberculosis is one of the most common and deadly diseases in the World. Up to one third of the Worlds population has been infected with the bacterium Mycobacterium tuberculosis but does not have active disease," said Gerald W. Fischer, MD, CEO of Longhorn Vaccines and Diagnostics. "The heat shock protein may play a significant role in shielding the bacterium from the immune system and allowing it to survive. The data being presented suggests that both our heat shock protein vaccine candidate and monoclonal antibody cocktail could play a significant role in preventing and treating multi-drug resistant tuberculosis infections."

Mycobacterium tuberculosis (MTB) is a virus that is becoming increasingly resistant to antibiotics and a key pathogen contributing to antimicrobial resistance worldwide. The third study, conducted by the University of Pretoria, explored Longhorns monoclonal antibodies for the prevention and treatment of infections caused by MTB and gram-positive bacteria. The study analyzed the binding capabilities of IgG2a (anti- heat shock protein (HSP16.3)) and IgG2b (anti- Peptidoglycan (PGN)) mAbs to clinical MTB isolates. Results found:

Both IgG2a and IgG2b mAbs demonstrated good binding activity to live and ethanol-killed MTB, and to mid-logarithmic and stationary phase MTB.

The mAbs demonstrated good binding to live clinical MTB isolates at concentrations as low as 0.25 g/mL.

For more information about Longhorn, visit http://www.LHNVD.com.

About Longhorn Vaccines and Diagnostics

Longhorn Vaccines and Diagnostics is a closely held One Health company based in Maryland that is developing broad coverage vaccines and diagnostic tools for worldwide public health concerns and to prevent future pandemics. Since its inception in 2006, Longhorn has focused on developing broad coverage vaccines and diagnostic tools that can impact a pandemic on a global scale and at all socio-economic levels. Since pandemics flow between humans and animals, Longhorn products play a significant role to surveil, diagnose, prevent and treat the next infectious disease.

View source version on businesswire.com: https://www.businesswire.com/news/home/20240427410246/en/

Contacts

Longhorn Vaccines and Diagnostics LLC Jeffrey Fischer Email: jeff@lhnvd.com

Media Alexis Feinberg ICR Westwicke PR Email: alexis.feinberg@westwicke.com

Investor Relations Stephanie Carrington ICR Westwicke IR Email: stephanie.carrington@westwicke.com

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Longhorn Vaccines and Diagnostics Presents New Data on its Best-In-Class Infectious Disease Vaccine and Antibody ... - Yahoo Finance

With whooping cough cases on the rise, do you need a booster vaccine? – Fox News

April 24, 2024

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As whooping cough cases are surging globally, some may wonder if its necessary to get a booster.

Cases of the childhood respiratory disease also known as pertussis are surging internationally and in parts of the U.S., according to a recent report.

Bordetella pertussis is a type of bacteria that causes a very contagious respiratory infection that spreads from person to person through small respiratory droplets, per the CDC.

NEW YORK HEALTH OFFICIALS WARN OF WHOOPING COUGH OUTBREAK AMONG CHILDREN

"Reports indicate that whooping cough outbreaks are surging across Europe, Asia and parts of the United States, including Northern California, marking the largest uptick since 2012, with cases rising sharply since December," Maggie Rae, president of the Royal Society of Medicines epidemiological and public health section in London, told Fox News Digital.

Bordetella pertussis is a type of bacteria that causes a contagious respiratory infection that spreads from person to person through small respiratory droplets, per the CDC. (iStock)

In the U.K., there were an estimated 555 cases in January of this year and 913 cases in February compared to 858 cases for all of 2023, according to the UK Health Security Agency.

Cases in China totaled more than 15,000 this January. That's 15 times higher than the same time period last year, reports stated.

AMID CHILDHOOD PNEUMONIA OUTBREAKS, INFECTIOUS DISEASES EXPERT REVEALS KEY FACTS ABOUT WHITE LUNG SYNDROME

"Concerns are mounting in Europe, especially in the Netherlands, where 1,800 cases were reported in the first two weeks of April, leading to four deaths, with declining childhood vaccination rates cited as a possible cause by public health officials," Rae said.

"This is a very important public health issue, and I would urge those members of the public who require a vaccine for pertussis to take this up."

Whooping cough is mostly controlled in the United States, although "breakthrough cases" can occur in people who are fully vaccinated.

Cases of the childhood respiratory disease known as whooping cough or pertussis are surging internationally and in parts of the U.S., according to a recent report. (iStock)

Clusters of cases in certain parts of the U.S. are expected for this time of year, according to the Centers for Disease Control and Prevention (CDC).

There have been small "clusters" of cases of whooping cough in the U.S., extending from San Francisco to New York City.

CDC RECOMMENDS ADDITIONAL COVID VACCINE FOR ADULTS 65 AND OVER

A Catholic high school in San Francisco, California, has reported more than 12 cases since January, according to local reports.

The New York City Department of Health and Mental Hygiene estimated 244 cases from Oct. 1, 2023, to Jan. 31, 2024.

That's a 200% increase compared to the same time period in the prior year, a recent health advisory stated.

"This is a very important public health issue."

Most unvaccinated cases involved infants, while most vaccinated individuals were school-aged children.

A majority of adults had an unknown vaccination history, the advisory noted.

The U.S. typically has approximately 20,000 cases of pertussis per year. Yet as people donned masks and practiced physical distancing during the pandemic, annual cases dropped to 6,124 in 2020 and 2,116 in 2021, according to the CDC.

Clusters of cases often occur where there are large groups of young people, such as child care centers and schools.

"The symptoms of pertussis are initially like a cold, with a runny nose, and progress to a cough," Jennifer Duchon, M.D., hospital epidemiologist and director of antimicrobial stewardship at Mount Sinai Kravis Children's Hospital in New York, told Fox News Digital.

Patients tend to develop a cough that can become severe sometimes to the point of vomiting, Duchon said.

Health care providers typically test for the disease with a nasal swab. (iStock)

"The characteristic whooping sound is a gasp that is made when trying to breathe after a long episode of coughing," she added.

The cough can linger for weeks after a person catches pertussis.

When outbreaks occur, babies are at a high risk of getting sick and dying from the infection, health officials warn.

AS NEW JERSEY INVESTIGATES MUMPS OUTBREAK, EXPERTS SHARE WHAT TO KNOW ABOUT SYMPTOMS, PROTECTION

"Pertussis is most severe in infants 6 months of age or less, especially in infants who were born preterm or are not immunized," Duchon said.

"Young infants can have a severe cough that impairs their ability to breathe, and can lead to episodes where they vomit, struggle to breathe or even cease breathing after bouts of coughing."

Patients tend to develop a cough that can become severe sometimes to the point of vomiting, a doctor said. "The characteristic whooping sound is a gasp that is made when trying to breathe after a long episode of coughing." (iStock)

Babies often wont make that whooping sound, so a warning sign is when their face turns blue as they struggle to breathe, the CDC noted.

The infection can progress to bacterial pneumonia or a condition called pulmonary hypertension, in which heart function is affected by the disease, Duchon warned.

Health care providers typically test for the disease with a nasal swab.

"If pertussis is caught early, patients can take an antibiotic called azithromycin, but this only helps make the disease less severe and does not cure the disease," Duchon noted.

MEASLES VACCINATIONS GIVEN IN '70S AND '80S MAY HAVE WORN OFF BY NOW, DOCTOR WARNS

"If someone is exposed to pertussis and is at risk for severe disease or had a lot of contact with the ill person, doctors will sometimes recommend a short course of an antibiotic to act as a prophylaxis against the disease."

Currently, there are two kinds of vaccines for whooping cough available in the U.S., according to the CDC.

"The best way to prevent the disease is to make sure that all family members and health care workers are up-to-date on their vaccinations not only for pertussis, but also other vaccine-preventable diseases," Duchon told Fox News Digital.

"Children should get their primary series of vaccines at 2 months, 4 months and 6 months, and then at 15 months through 18 months, and at 4 years through 6 years," a doctor advised. (iStock)

The DTaP vaccine protects against diphtheria, tetanus and pertussis.

The Tdap vaccine protects against tetanus, diphtheria and pertussis.

The DTaP vaccine is for babies, while the Tdap "booster" vaccine is for pre-teens, teenagers and adults, per the CDC.

"Before vaccination became available, the disease used to be a major cause of mortality in young children," Duchon noted.

Due to the high risk to babies, the CDC recommends that pregnant women receive the Tdap vaccine during the 27th and 36th week of pregnancy, regardless of their prior vaccination status.

This prevents 78% of cases in infants younger than 2 months old and decreases hospitalization by 90% for infants younger than 2 months old who are infected with pertussis, according to the CDC.

"Everyone in close contact with a very young infant should be vaccinated against pertussis."

It is recommended that babies get immunized with the DTaP vaccine series, which provides immunity for three separate infectious diseases diphtheria, tetanus and pertussis.

"Children should get their primary series of vaccines at 2 months, 4 months and 6 months, and then at 15 months through 18 months, and at 4 years through 6 years," Duchon advised.

The Tdap vaccine protects against tetanus, diphtheria and pertussis. (iStock)

Adolescents should receive the Tdap vaccine at 11 to 12 years old to boost their immunity, the CDC recommends.

In children who receive the full series, 98% have full protection against the infection within a year after the last dose, but the response decreases to 71% after five years, the agency states.

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As pertussis immunity wanes from the original vaccination series in childhood, adults should get regular boosters, Monica Gandhi, M.D., professor of medicine and an infectious disease specialist at UCSF/ San Francisco General Hospital, told Fox News Digital.

"Although the exact frequency of the need for booster vaccination has not been precisely worked out, we recommend a tetanus vaccine every 10 years," she said.

The DTaP vaccine protects against diphtheria, tetanus and pertussis. (iStock)

As the pertussis vaccine comes formulated with tetanus immunization in the form of the Tdap vaccine, many practitioners recommend a pertussis vaccine every 10 years when the booster for tetanus is provided, according to Gandhi.

Other providers may only recommend routine pertussis boosters in certain circumstances, such as for pregnant women or adults who have never been vaccinated, Duchon added.

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"Everyone in close contact with a very young infant should be vaccinated against pertussis," she said.

"We call this strategy cocooning, where those around the baby form a protective wall against the disease."

For more Health articles, visit http://www.foxnews.com/health.

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With whooping cough cases on the rise, do you need a booster vaccine? - Fox News

Maine reaches a milestone for school-required vaccinations – Press Herald

April 24, 2024

Maine has reached herd immunity for school-required vaccination coverage for the first time since 2011, driven by a law that went into effect in 2021 that eliminated philosophical and religious exemptions for students attending K-12 schools.

Herd immunity is achieved when at least 95% of a population is immunized against infectious diseases.

Maine has become a leader in childhood vaccination, Dr. Puthiery Va, director of the Maine Center for Disease Control and Prevention, said in a statement Tuesday. It couldnt come at a better time, as the United States has already seen more measles cases in the first three months of 2024 than in all of 2023. This alarming trend highlights the importance of childhood vaccinations, which reduce the risk that Maines youngest residents could face from these harmful and potentially fatal diseases.

The U.S. CDC is reporting 125 cases of measles in 17 states (none in Maine) so far in 2024.

State lawmakers and the Mills administration prioritized improving Maines vaccination rates after years of high rates of religious and philosophical opt-outs left the state vulnerable to outbreaks of infectious diseases.

Lawmakers passed the bill in 2019, and it survived a peoples veto attempt that would have overturned the law before it was implemented. The new vaccine law went into effect in the 2021-22 school year.

Since then, as families have complied with the new requirements, vaccination coverage in schools has improved, plummeting from 4.5% opting out in 2020-21 the last year before the law was implemented to 0.8% in 2022-23 and 0.9% in 2023-24.

Medical exemptions are still permitted under the law, but religious and philosophic exemptions are no longer allowed.

Meanwhile, the percentage of students getting their first shots for diseases covered by school vaccination requirements including measles, mumps and rubella, pertussis, polio and others surpassed 95% for the first time since 2011, the Maine CDC said.

Herd immunity is the scientific term for when vaccination coverage among a population is so comprehensive that infectious diseases have few opportunities to gain a foothold. Public health experts say herd immunity is important in preventing highly contagious diseases from spreading in populations.

Achieving herd immunity among schoolchildren represents a pivotal success for Maine, Jeanne Lambrew, commissioner of the Maine Department of Health and Human Services, said in a statement.

The percentage of students immunized against specific diseases can differ from the overall vaccination rate for several reasons, primarily because of missing vaccination records. Even if a parent has their child vaccinated, the child will be listed as unvaccinated if the school doesnt have the vaccination record to turn over to the state CDC.

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Maine reaches a milestone for school-required vaccinations - Press Herald

Scientists Are Extremely Close to Creating One Vaccine For All Strains of the Same Virus | Weather.com – The Weather Channel

April 24, 2024

Representational image of a vaccine

The coronavirus was one tough cookie to beat. Much like the mythological Hydra, if you managed to kill one of its variants, it only came back with a stronger and meaner version, which often required an entirely new type of intervention (read: booster doses) to slay. Such is the fight against viruses in general, and why we still havent beaten the common cold, which has since mutated to 160 different strains now.

For this reason, coming up with a master vaccine that can eliminate all strains of the same family of viruses has seemed like a pipe dream ever since we started researching antivirals. However, scientists are pioneering a new vaccine platform that could do just that! And at the heart of this innovation lies one of the fundamental blocks of our cells: RNA.

For a refresher, RNAs are the intermediaries between the DNA and the protein-making process. Think of the DNA as a blueprint that tells you exactly how to make something, say, a house. The RNA copies the blueprint bit by bit and takes this message to centres with building materials, where the house can actually be constructed.

When a host is infected, their body produces small amounts of RNAs as an immune response to a viral infection. These fighters are called RNAis, and help kill the virus. To get around this setback, the viruses produce proteins that block the RNAi response.

The new technique attempts to manipulate the virus protein-manufacturing process in their new vaccine. Unlike traditional vaccines, which rely on the body's immune response, this method activates RNAi, offering a novel approach to viral defense.

The scientists found that if you weaken the virus first, it hinders their ability to block RNAi.

It (the virus) can replicate to some level, but then loses the battle to the host RNAi response. A virus weakened in this way can be used as a vaccine for boosting our RNAi immune system, explains study author Shouwei Ding.

This new method even addresses the everlong mutation problem too. While traditional vaccines focus on deactivating a specific part of the virus to destroy them, the new RNAi method targets their whole genome, meaning that it will work for any future mutated strains as well. Or as the study authors put it, they cannot escape this.

Moreover, this platform presents a game-changer for vulnerable populations such as infants and individuals with compromised immune systems. By bypassing the need for traditional B and T cell immune responses, this vaccine holds promise for those typically ineligible for live vaccines.

Initial trials on mice, including genetically modified newborns devoid of B and T cells, have yielded promising results. A single injection provided robust protection against the Nodamura virus for an extended period, showcasing the platform's efficacy and potential longevity.

Looking ahead, the researchers aim to adapt this technology to tackle influenza, with plans for a nasal spray vaccine to alleviate needle-related concerns.

Our next step is to use this same concept to generate a flu vaccine, so infants can be protected. If we are successful, theyll no longer have to depend on their mothers antibodies, Ding notes.

While challenges remain, including extensive human trials and regulatory approvals, the prospect of universal protection against a spectrum of viruses looms tantalisingly close. With one shot, we could be looking to neutralise a multitude of human pathogens, including dengue, SARS and COVID.

The findings of this study have been published in Proceedings of the National Academy of Sciences and can be accessed here.

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Scientists Are Extremely Close to Creating One Vaccine For All Strains of the Same Virus | Weather.com - The Weather Channel

Pfizer vs Moderna battle over COVID vaccine patents begins in UK – Yahoo Finance

April 24, 2024

By Sam Tobin

LONDON (Reuters) - Pfizer and BioNTech asked a London court to revoke rival Moderna's patents over technology key to the development of vaccines for COVID-19, as the latest leg of a global legal battle began on Tuesday.

Pfizer and its German partner BioNTech sued Moderna at London's High Court in September 2022, seeking to revoke patents held by Moderna, which hit back days later alleging its patents had been infringed.

The competing lawsuits over the companies' two vaccines, which helped save millions of lives and made the companies billions of dollars, are just one strand of ongoing litigation around the world which focuses on messenger RNA (mRNA) technology.

Moderna says Pfizer and BioNTech copied mRNA advances it had pioneered and patented well before the COVID-19 pandemic began in late 2019.

U.S.-based Moderna is seeking damages for alleged infringement of its patents by Pfizer and BioNTech's Comirnaty shot on sales since March 2022.

Pfizer made $11.2 billion in sales from Comirnaty last year, while Moderna earned $6.7 billion from its vaccine Spikevax, illustrating the potentially huge sums at stake.

Pfizer and BioNTech, however, are asking the High Court to revoke Moderna's patents, arguing that Moderna's developments of mRNA technology were obvious improvements on previous work.

The London lawsuits have been split into three separate trials, with one due to consider Moderna's 2020 pledge not to enforce its vaccine-related patents during the pandemic starting next.

Pfizer, BioNTech and Moderna are also involved in parallel proceedings in Germany, the Netherlands, Belgium and the United States, much of which has been put on hold, as well as at the European Patent Office.

(Reporting by Sam Tobin; Editing by Sachin Ravikumar)

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Pfizer vs Moderna battle over COVID vaccine patents begins in UK - Yahoo Finance

A comprehensive synthetic library of poly-N-acetyl glucosamines enabled vaccine against lethal challenges of … – Nature.com

April 24, 2024

Synthesis of the PNAG oligosaccharide library

To date, only fully acetylated and fully deacetylated PNAG oligosaccharides have been investigated as immunogens for vaccine studies13,14,15. The availability of a library of PNAG oligosaccharides with systematically varied numbers and locations of free amines can greatly aid in the identification of the maximally protective epitope structures. We aimed to synthesize a comprehensive library of 32 pentasaccharides designated PNAG0PNAG31 (Fig.1) fully covering the free amine space of PNAG. The reducing ends of the target pentasaccharides bear a linker terminated with a disulfide group, which can be reduced for chemoselective conjugation to a carrier protein.

The five-digit number in the bracket for each compound codes for free amine (0) or N-acetamide (1) at residues ABCDE from the non-reducing end to the reducing end of the pentasaccharide, respectively. The five-digit number was then viewed as a binary number and converted to the decimal system as the compound number. For example, 01010 in binary number is equivalent to 10 in the decimal system. Thus, the PNAG pentasaccharide bearing N-acetylation at units B and D only is named as PNAG10.

While several PNAG structures have been synthesized before16,17,18,19,20, a general method for the expeditious construction of a comprehensive PNAG pentasaccharide library is lacking. To accelerate the library synthesis, rather than starting from monosaccharide building blocks for each targeted pentasaccharide, we envisioned the overall efficiency can be significantly enhanced with a divergent strategy. In our synthetic design, the amine groups of strategically protected pentasaccharides are differentiated by orthogonal protective groups for selective deprotection and acetylation. After screening multiple synthetic intermediates, we developed two key linchpin pentasaccharide intermediates (1 and 2), which bear four protective groups, i.e., tert-butyloxycarbonyl (Boc), allyloxycarbonyl (Alloc), 2,2,2-trichloroethoxycarbonyl (Troc), and fluorenylmethoxycarbonyl (Fmoc), on glucosamine units A, B, C, and D. The reducing end glucosamine unit E is N-acetylated (for compound 1) or N-trifluoroacetylated (for compound 2) (Fig.2A).

A Structures of two key linchpin pentasaccharide intermediates (1 and 2). B Synthesis of the reducing end glucosamine building block 8. C Syntheses of compound 13; D Syntheses of compound 1. Ac acetyl, Alloc allyloxycarbonyl, Bz benzoyl, TBDPS tert-butyldiphenylsilyl, Boc tert-butyloxycarbonyl, DIPEA diisopropylethylamine, Fmoc fluorenylmethoxycarbonyl, HATU hexafluorophosphate azabenzotriazole tetramethyl uronium, and Troc 2,2,2-trichloroethoxycarbonyl.

Based on the above design, our synthesis commenced from thioglycoside 3, which glycosylated 3-azido-1-propanol 4 to provide compound 5 in 82% yield (Fig.2B). Upon removal of the Alloc group from 5 and N-acetylation, the resulting compound 6 was subjected to azide reduction, amidation of the free amine with carboxylic acid 7, and protective group adjustments leading to compound 8 in 45% yield for the four steps.

Oligosaccharide assembly started from the CD disaccharide 9 containing N-Troc and N-Alloc groups (Fig.2C). Thioglycoside donor 10 was preactivated with the p-TolSCl/AgOTf promoter system21 at 78C. Upon complete activation, the thioglycosyl acceptor 11 was added to the reaction mixture leading to disaccharide 9 in 83% yield (Fig.2C). In order to extend the glycan chain, the glycosylation of acceptor 8 with disaccharide 9 was performed. When the reaction was first carried out under the pre-mix condition, i.e., 9 and 8 were mixed together followed by the addition of promoter (p-TolSCl/AgOTf or NIS/TfOH22,23), little desired trisaccharide 12 was obtained, which was likely due to the activation of the thioester moiety by the thiophilic promoter. Next, the reaction was explored under the pre-activation condition by activating 9 with the promoter p-TolSCl/AgOTf first, followed by the subsequent addition of acceptor 8. This change of the reaction protocol successfully produced trisaccharide 12 in 71% yield. Replacement of Alloc with Fmoc and removal of TBDPS group from 12 resulted in the trisaccharide 13. To extend 13 to a pentasaccharide, the Troc moiety of disaccharide 9 was replaced with Boc (disaccharide 14, Fig.2D). Pre-activation-based glycosylation of 14 and 13 produced pentasaccharide 1, which contains four different N-protective groups on units A, B, C, and D. Analogously, pentasaccharide 2 was synthesized with four different N-protective groups on units A, B, C, and D, and the N-TFA group on unit E (Supplementary Fig.1).

With the two key pentasaccharides in hand, we explored orthogonal deprotection of pentasaccharides 1 and 2. As an example, the Boc and Alloc groups of compound 2 could be removed by 90% aqueous TFA and Pd(PPh3)4/PhSiH3, while deprotections of Troc and Fmoc were accomplished using Zn/AcOH and 20% piperidine in N,N-dimethylformamide (DMF), respectively, without affecting any other amine protective groups (Fig.3A). These results suggest that the four amine protective groups could be independently removed specifically.

A Orthogonal deprotection of pentasaccharide 2. B Divergent syntheses of 16 PNAG pentasaccharides from the strategically protected pentasaccharide 1. C Divergent syntheses of 16 PNAG pentasaccharides from the strategically protected pentasaccharide 2. Ac acetyl, Alloc allyloxycarbonyl, Bz benzoyl, TBDPS tert-butyldiphenylsilyl, Boc tert-butyloxycarbonyl, DIPEA diisopropylethylamine, DMF dimethylformamide, Fmoc fluorenylmethoxycarbonyl, HATU hexafluorophosphate azabenzotriazole tetramethyl uronium, Troc 2,2,2-trichloroethoxycarbonyl, and TFA trifluoroacetic acid.

With the orthogonal deprotection conditions established, divergent modifications of the key pentasaccharide intermediates were carried out. Treatment of pentasaccharide 1 with 90% TFA cleaved both Boc and TBDPS groups (Fig.3B). Upon acetylation of the newly liberated hydroxyl and amine moieties, the Alloc, Troc, and Fmoc groups were subsequently removed followed by full O- and S-deacylation with 20% hydrazine hydrate in MeOH, affording PNAG17 pentasaccharide in 48% overall yield bearing the N-acetylglucosamine (GlcNAc)-glucosamine (GlcN)-GlcN-GlcN-GlcNAc (10001) sequence. Alternatively, following TFA treatment of 1, the Fmoc group was cleaved, which was then acetylated with subsequent removal of Troc, Alloc, and Bz moieties to produce pentasaccharide PNAG19 with the GlcNAc-GlcN-GlcN-GlcNAc-GlcNAc sequence (10011) in 51% overall yield. Similar divergent modification processes on the two key pentasaccharides 1 and 2 produced the full library of 32 PNAG pentasaccharides with all possible combinations of free amines in each glucosamine unit of the pentasaccharides (Fig.3B, C).

As carbohydrate antigens in general are T cell independent B cell antigens24 and small oligosaccharides alone are not immunogenic25, these types of antigens need to be conjugated to an immunogenic carrier in order to induce anti-carbohydrate IgG antibody responses. The mutant bacteriophage Q (mQ)26 is a powerful carrier and likely highly useful for carbohydrate based conjugate vaccines27,28,29. As PNAG oligosaccharides can potentially contain multiple free amine moieties, we resorted to sulfhydryl chemistry for PNAG/mQ conjugation. The mQ A38K/A40C/D102C was expressed in E. coli, purified, and incubated with the bifunctional linker succinimidyl 3-(bromoacetamido)propionate (SBAP) 19 to react with free amines on the mQ surface (Fig.4A). Upon removal of the excess linker, the SBAP functionalized mQ was added to the PNAG pentasaccharide followed by quenching the unreacted bromoacetamide moieties on mQ with cysteine to avoid any potential side reactions of residual bromoacetamide on mQ upon storage or following vaccination. MALDI-TOF mass spectrometry (MS) analysis of the mQPNAG conjugate showed an average loading of 250 copies of pentasaccharide per particle (Supplementary Fig.2A). It is known that the antigen loading density on Q can significantly impact the levels of antibodies induced against the target antigen29,30. When the loading level of antigen was low (<50 copies per particle), despite the same total amount of antigen administered, the antibody responses induced were low29,30. Increasing the local density of the antigen on the particle (over 100 antigens per particle) can significantly improve the antibody responses, which is presumably due to the more effective crosslinking of the B cell receptors on B cells31. The loading density of PNAG on the mQPNAG conjugate was higher than the threshold antigen level needed for powerful B cell activation.

Syntheses of A mQPNAG, B TTHcPNAG, and C BSAPNAG conjugates. SBAP succinimidyl 3-(bromoacetamido)propionate, TCEP tris(2-carboxyethyl)phosphine, TThc tetanus toxoid heavy chain.

With the mQPNAG conjugates in hand, their abilities to induce anti-PNAG antibodies were evaluated. The conjugate of TT with the PNAG pentasaccharide bearing five free amines (5GlcNH2TT) has undergone a phase 1 human clinical trial32. To compare with our mQPNAG conjugate, we covalently linked PNAG0 (5GlcNH2) with the TT heavy chain (TTHc) using SBAP and achieved an average loading of 4.7 PNAG0 per protein molecule (Fig.4B and Supplementary Fig.2B). The recombinant TTHc is a suitable surrogate of TT33. As the molecular weight of mQ particle (2540kDa for the protein shell) is about 49 times that of the TTHc (MW~52kDa), the overall densities of PNAG0 on mQPNAG0 and TTHcPNAG0 were similar.

Head-to-head comparative immunogenicity studies of the mQPNAG0 and the TTHcPNAG0 conjugates were carried out. Groups of female C57Bl6 mice (n=5 per group) were immunized with freshly prepared mQPNAG0 (8nmol corresponding to 8g of PNAG0 per injection) or the TTHcPNAG0 conjugate (8nmol PNAG0 per injection) on days 0, 14, and 28. Monophosphoryl lipid A (MPLA, 20g) was added to each vaccination as the adjuvant. A control group of mice received a mixture of mQ with PNAG0 at equivalent total amounts of mQ, PNAG0, and MPLA following the same immunization protocol. On day 35, sera were collected from all mice.

To analyze the levels of antibodies generated, enzyme linked immunosorbent assay (ELISA) analyses were performed. To avoid the interference of anti-mQ antibodies in the sera, the 32 PNAG pentasaccharides were conjugated with BSA individually (Fig.4C and Supplementary Fig.3) and used as the ELISA coating antigens. As shown in Fig.5A, mQPNAG0 induced high anti-PNAG IgG titers (EC50 IgG titers GMT 75,613, measured against BSAPNAG0) while the IgM titers were negligible (GMT<1000). Furthermore, high levels of anti-PNAG0 IgG responses were observed more than 1 year after the initial immunization (Fig.5B). The IgG levels could be boosted back to near peak levels after nearly 2 years indicating that the mQ conjugate induced PNAG0 specific memory B cells through immunization. The GMT of 75,613 achieved in mice receiving the mQPNAG0 was significantly (P<0.0001, Dunnetts multiple comparisons test) higher than the anti-PNAG0 IgG titers achieved in mice immunized with the corresponding TTHcPNAG0 conjugate (GMT 4765), highlighting the superior immunogenicity of the mQ carrier for conjugate vaccines. Mice immunized with the admixture of mQ and PNAG0 did not produce any detectable levels of anti-PNAG0 IgG (GMT<1000), accentuating the critical need to covalently conjugate mQ with PNAG0.

A C57Bl6 mouse (n=5 per group) antibody responses at day 35 after immunization. The EC50 value (the fold of serum dilution that gives half-maximal binding) of the IgG titers to the immunizing oligosaccharide was plotted with each symbol representing one animal and the horizontal line is the geometric mean value of the titers within the group. The ELISA titers were determined using the BSAPNAG conjugate containing the same PNAG structure as the immunizing QPNAG construct. One-way ANOVA allowed for rejection of the null hypothesis that all groups have the same mean IgG titers (P<0.0001). Statistical significance was performed by Dunnetts multiple comparisons post-hoc test. ****P<0.0001; B Anti-PNAG0 IgG antibody responses of mice (n=5) immunized with mQPNAG0 monitored over time with mean titers plotted. Data are presented as mean valuesstandard deviation of the titer numbers from five mice. The arrows indicate days of vaccination (days 0, 14, 28, 360, and 655). The antibody responses could be boosted more than 650 days after prime vaccination. Source data are provided as a Source Data file.

As C57Bl6 mice are inbred, to enhance the rigor of our study, we immunized outbred CD1 mice with the mQPNAG0 conjugate following the same immunization protocol. mQPNAG0 was able to elicit comparably high titers of anti-PNAG0 IgG antibodies on day 35 after the primary series of immunization in CD1 mice (Supplementary Fig.4).

The precise PNAG sequences synthesized by pathogens such as S. aureus are not known. Furthermore, the most abundant PNAG structure on cell surfaces that would encompass a highly (8095%) acetylated polysaccharide is not a protective epitope13. To guide vaccine design, we envisioned anti-PNAG mAb F598 could provide valuable information regarding optimal acetylation patterns in a PNAG pentasaccharide. Isolated from a patient who recovered from an S. aureus infection, mAb F598 can protect mice against S. aureus infections34. The 32 PNAG pentasaccharideBSA conjugates were immobilized onto a glycan microarray35. Following incubation of mAb F598 with the microarray and washing, the amount of antibody remaining bound was quantified with a fluorescent secondary antibody. Interestingly, although mAb F598 was initially identified due to binding to deacetylated PNAG with only ~15% N-acetylation34, it had little binding to glycan PNAG0 or any glycans containing only one Ac moiety. Highly acetylated PNAG such as PNAG30 and PNAG31 with four or more consecutive GlcNAcs were among the strongest binders (Fig.6). Both the location and the number of NHAc are important for F598 binding, supporting the idea of an amine/acetylation code. For example, despite having the same total number of NHAcs (4 in the molecules), PNAG23 (10111) is a weak binder with an apparent affinity <5% of that with PNAG30 (11110). Out of the PNAGs with two or three GlcNAc residues, PNAG10 and PNAG26 were the strongest binders, respectively.

A Relative fluorescence unit (RFU) of F598 mAb binding with the library of 32 PNAG pentasaccharides. The glycans are grouped according to the number of NHAc units in the molecule. Each PNAG sequence is printed five times on the glycan microarray. The error bars represent the standard deviations of five individual spots. Data are presented as mean valuesstandard deviation. F598 generally prefers highly acetylated PNAG sequences. Both the location and the number of NHAc units are important determinants of F598 binding. B Quantification of the preference of F598 for acetylation at each site of the PNAG pentasaccharide. The mean values are calculated from the values of the binding intensities of all 32 PNAG sequences to F598. Each PNAG sequence is printed five times on the glycan microarray. Data are presented as mean valuesstandard deviation. Source data are provided as a Source Data file.

To better interpret the binding data, we quantified the GlcNAc binding preference of F598 by computing the preference index (P) for each unit of the pentasaccharide as

$${P}_{i}=frac{mathop{sum}limits_{j}{R}_{j}times {A}_{i}}{mathop{sum}limits_{j}{R}_{j}}$$

(1)

where (i) (AE) is the site of monosaccharide from the non-reducing end to the reducing end, (j) (031) is the serial number of glycan, (R) is the intensity of the binding signal (RLU), and (A) is the code for amine vs acetylation (A=1 for free amine and A=1 for NHAc). P value indicates the conditional probability difference between finding an NHAc or free amine for binding, which ranges from 1 to 1 with 1 and 1 indicating a complete preference for free amine or NHAc, respectively, at the specific site. As shown in Fig.6B, unit B position showed the highest P value of 0.91, suggesting on average that there is a 95.5% chance to find an NHAc moiety rather than a free amine on saccharide B for ligand binding with F598. The P values for sites A, C, and E were between 0.31 and 0.54 indictive of a moderate global preference for N-acetylation. There were almost no preferences for NHAc or free amine for site 5 as the P value at this site was close to 0.

The importance of an NHAc at unit B identified from microarray binding can be rationalized by the crystal structure of F598 complexed with fully acetylated PNAG oligosaccharides (PDB 6be4)36. The binding pocket of F598 could accommodate PNAG with five GlcNAc residues. The NHAc groups on saccharides B and D in the binding pocket were deeply inserted into the groove clamped by the heavy and the light chain of the mAb, forming multiple hydrogen bonds, while the NHAcs on units A, C, and E only had weak to moderate interactions with the antibody. The carbonyl oxygen of the NHAc on saccharide B forms a hydrogen bonding with light chain A32 backbone amide while bridging with light chain R52 residue via a water molecule. The carbonyl oxygen of NHAc on saccharide D also formed hydrogen bonds with light chain A97 backbone amide and the hydroxyl of heavy chain Y50. Those interactions supported the relatively high dependence of NHAc on sites B and D for the binding of F598.

Based on the microarray results and the report that antibodies raised against the fully acetylated PNAG antigen were poorly protective13,14,15, we selected PNAG10 and PNAG26 as new PNAG oligosaccharide antigens for further evaluations. PNAG10 has the strongest binding to F598 among all PNAG structures with two or fewer NHAcs, and PNAG26 is the best binder among all structures with three or fewer NHAcs. Both PNAG10 and PNAG26 have NHAcs on glycan sites B and D. PNAG0 was utilized as a positive control since the corresponding TTPNAG0 construct (5GlcNH2TT) has entered clinical trials [ClinicalTrials.gov Identifier: NCT02853617].

C57/Bl6 mice were immunized with the mQ conjugates of PNAG10 or PNAG26 following the aforementioned immunization protocol (8nmol PNAG, three injections on days 0, 14, and 28 with MPLA adjuvant). ELISA analysis of the immune sera showed significantly enhanced IgG antibody titers against the immunizing antigen (PNAG10 or PNAG26) with GMTs of 191,141 and 227,064 ELISA units, respectively, as compared to pre-immune sera (Fig.5A). Similarly, mQPNAG10 or PNAG26 conjugates induced high levels of anti-PNAG10 and anti-PNAG26 IgG antibodies, respectively, in CD1 mice (Supplementary Fig.4).

To demonstrate the immunogenicity of the mQ conjugates in an additional mammalian species, New Zealand white rabbits were immunized with mQ conjugates of PNAG0, PNAG10, and PNAG26 (8nmol PNAG per injection) following a similar prime-boost protocol as that used in the mouse study. ELISA analysis of the post-immune sera showed that all three constructs induced strong anti-PNAG IgG responses with EC50 titers over 100,000 ELISA units (Fig.7A), while those for the pre-immune sera were below 1000 ELISA units. No side effects due to vaccinations were observed in either rabbits or mice.

A IgG antibody titers to the immunizing PNAG oligosaccharide in rabbit (n=2 per group) sera on day 35 after prime vaccination. B IgG antibody titers in pooled rabbit sera from mQ-conjugate or 5GlcNH2TT conjugate immunized animals (n=2 per group) as well as titer of natural human IgG in pooled human serum against native PNAG polysaccharide purified from Acinetobacter baumannii. The numbers above symbols are the average titer numbers. Titers and 95% confidence intervals (CI) were determined by linear regression using log10 values of the average of replicate serum dilutions to determine the X intercept and 95% CI when Y=0.5 (OD405nm of ELISA plate reading). C Stacked bar graphs depicting the IgG signals at the serum dilution of 1:50,000 for each rabbit (n=2) immunized with mQPNAG0, mQPNAG10, and mQPNAG26 as well as pre-immune sera, respectively, on the array. The complete microarray results are provided in the Source Data file; D Normalized binding of the comprehensive library of PNAG pentasaccharides by IgG antibodies from post-immune sera of rabbits immunized with mQPNAG0, mQPNAG10, and mQPNAG26, respectively, as well as pre-immune sera. PNAG sequences are grouped together according to the total number of acetamides in the molecules. The color scale bar is shown on the right with 100% indicating the strongest binding to a PNAG component and 0% indicating the weakest binder. For each antigen, the two rows represent sera from two rabbits per group immunized with the specific construct. Source data are provided as a Source Data file.

We analyzed next the recognition of native PNAG using PNAG polysaccharide isolated from Acinetobacter baumannii37,38 as the coating antigen for ELISA. As shown in Fig.7B, control sera from rabbits immunized only with the Q carrier did not bind with PNAG. In contrast, sera from rabbits immunized with mQPNAG0, mQPNAG10, and mQPNAG26 exhibited strong binding with mQPNAG26 antiserum having the highest titer (1,584,983 ELISA units) to the native microbial polysaccharide. As a comparison, sera from the conjugate of 5GlcNH2TT13,15 immunized rabbit only gave a titer of 501 ELISA units (Fig.7B). Normal human sera containing natural antibodies to PNAG had an average ELISA titer of 631 ELISA units. These results further highlight the potential of mQPNAG conjugates as vaccines.

Analysis of the microarray binding by post-immune sera revealed selective PNAG epitope recognition by the post-immune sera (Fig.7D). Rabbits immunized with mQPNAG0 produced serum IgG antibodies exhibiting the strongest binding with the immunizing PNAG0 antigenic structure. Other good binders include PNAG1 and PNAG8, both having a single GlcNAc in the structure. Interestingly, for PNAG4 with the sequence of GlcN-GlcN-GlcNAc-GlcN-GlcN, although it also only contains one GlcNAc, it had much lower binding with the sera (about 30% that to PNAG1). This suggests that three or more consecutive GlcNs are important for binding by anti-PNAG0 sera.

mQPNAG10 immunized rabbits produced serum antibodies that preferentially bind to PNAG8 (01000) and PNAG10 (01010), which differ only by the GlcNAc in residue D indicating the non-reducing end GlcN-GlcNAc-GlcN may be the main epitope. Serum antibodies from mQPNAG26 (11010) immunized rabbits preferentially bound to PNAG25 (11001), PNAG26 (11010), PNAG8 (01000), and PNAG16 (10000) suggesting GlcNAc-GlcNAc-GlcN and GlcNAc-GlcN-GlcN may be part of the epitopes being recognized.

For an effective vaccine, it is important to establish that the post-immune sera bind not only the isolated antigen but also the antigen expressed on pathogen cells. We reacted S. aureus ATCC29213 cells with rabbit immune sera and the bound antibodies were detected by a fluorescently labeled anti-rabbit IgG secondary antibody. As shown in Supplementary Fig.5A, fluorescence microscopy images showed stronger binding to bacterial cells by IgG antibodies in mQPNAG10 and mQPNAG26 immune sera compared to sera from mQPNAG0 immunized rabbits or pre-immune sera. To validate pathogen recognition observed in fluorescence images, whole cell ELISA was performed. S. aureus cells were coated on ELISA plates, incubated with rabbit immune sera, and detected by secondary antibodies. The post-immune sera exhibited significantly higher titers in binding with the cells compared to pre-immune sera (Supplementary Fig.6).

For antibody-mediated complement deposition39, we added various immune sera to wells coated with purified PNAG isolated from Acinetobacter baumannii37,38 along with IgG/IgM depleted 2.5% human complement (Fig.8A). After incubation, the immobilized complement component C1q was detected by anti-C1q antibodies. As shown in Fig.8A, sera from mQPNAG10 and mQPNAG26 deposited significantly more C1q than those from mQPNAG0 immunized rabbits, which in turn had more potent C1q binding than antibodies in sera from rabbits immunized with the 5GlcNH2TT conjugate13,15.

A Complement deposition tests were performed as described39 using pooled sera from rabbits (n=2 per group) immunized with mQPNAG conjugates, the 5GlcNH2TT conjugate, or from a sample of pooled normal human sera. Titers and 95% confidence intervals (CI) were determined by linear regression using log10 values of the average of replicate serum dilutions to determine the X intercept and 95% CI when Y=0.5 (OD405nm of ELISA plate reading). P values indicate the significance of the deviation of the slope of the titration curve from zero to identify sera with activity at P<0.05. mQPNAG10 and mQPNAG26 conjugates were more potent than the mQPNAG0 and 5GlcNH2TT conjugate in inducing C1q deposition onto purified PNAG. Normal human serum had no significant C1q depositing activity in spite of having a binding titer to PNAG (see Fig.7B) consistent with prior reports that naturally acquired human antibody to PNAG is not functional due to the inability to activate the complement pathway12,34. Titers were determined by simple linear regression. B Pooled sera from rabbits (n=2 per group) immunized with mQPNAG conjugate led to significantly higher levels of opsonic killing activities against S. aureus cells. Three aliquots were prepared from each pooled serum and the individual values of the three aliquots were presented. Source data are provided as a Source Data file.

The abilities of the post-immune sera to kill bacteria in vitro were evaluated next via the opsonophagocytic killing (OPK) assay. S. aureus cells were treated with pooled rabbit immune sera, followed by the addition of complement/phagocytic cells and quantification of the number of bacterial cells surviving the opsonic killing. As shown in Fig.8B, while the pre-immune sera were completely ineffective, all three constructs induced antibodies with potent in vitro killing activity. mQPNAG26 (EC50: 2534) and mQPNAG10 (EC50: 3045) showed higher EC50 OPK titers as compared to mQPNAG0 (EC50: 1345). Omitting either immune sera, complement or phagocytic cells resulted in complete loss of killing activity (Supplementary Fig.7), indicating the need for all three components for protective immunity.

The efficacy of the various vaccine constructs in protecting against bacterial infection was tested in two mouse bacteremia challenge models. According to the CDC, bloodstream infections by S. aureus are serious threats with nearly 20,000 deaths per year in the USA4. For the in vitro study, we first compared the mQPNAG0 vs TTHcPNAG0 construct. In the active protection model, mice were immunized three times with mQPNAG0 or TTHcPNAG0 at equivalent doses (8nmol PNAG0) (n=20 for each group) (Fig.9). Another group of control mice received a mock injection of saline. Two weeks following the last vaccination, each mouse was challenged via the tail vein with 10*LD50 of the S. aureus strain ATCC29213. Mice that had received saline all died within 2 days of bacterial challenge. On the other hand, 95% of the mice receiving mQPNAG0 were protected against death from this pathogen. The survival rate of the mQ vaccine group was significantly better than TTHcPNAG0 vaccinated group (p=0.0154, logrank test) (Fig.9A). Bacteria were detected in the kidneys of 35% (7 out of 20) of the mice immunized with TTPNAG0, while mQPNAG0 vaccination reduced the recovered levels of S. aureus from the kidneys with bacteria only observed in 5% of the mice (1 out of 20) (Fig.9B). Contingency table analysis of the proportion of the 20 immunized mice in each group with or without detectable S. aureus by Fishers exact test showed significantly (p=0.0436) fewer infected kidneys in the mQPNAG0 immunized group, with a relative risk of 0.68 (95% CI=0.450.93). Thus, disease burden evaluated by the levels of S. aureus in mouse kidneys was significantly better in mQPNAG0 vaccinated group compared to those receiving the TTHcPNAG0 vaccine. These results further support the superior performance of the mQ carrier.

Immunization with mQPNAG0 effectively A protected against S. aureus infection, and B reduced bacterial count in mouse kidney. mQPNAG0 was significantly better than TTHcPNAG0 in protecting mice and reducing disease burden (n=20 for each group). Logrank tests were performed for statistical analysis. P values were presented in the graph. ****P<0.0001. Source data are provided as a Source Data file.

As the mQPNAG0 immunogen gave almost complete protection in the active protection model in mice, we next established a passive protection model to differentiate the various mQPNAG constructs, using rabbit sera transferred to mice. The passive model can be a more stringent test by using more dilute sera for protection. Rabbit sera were diluted 800-fold and administered intraperitoneally to mice, which were then challenged with 10*LD50 (200 million cells) of S. aureus ATCC29213 via the tail vein (Fig.10). While all control mice receiving the pre-immune sera died within 3 days of this challenge, all post-immune sera from PNAG0, PNAG10, or PNAG26 immunized rabbits bestowed significant protection.

Transfer of antisera from mQPNAG immunized rabbits to mice A provided significant protection to mice (n=10 per group) against the lethal challenges by S. aureus ATCC29213. Statistical analysis was performed with the logrank test. ****P<0.0001; and B significantly reduced bacterial count in mouse kidneys. The combination of sera from mQPNAG0 and mQPNAG26 immunized rabbits provided complete protection to mice. Statistical analysis for survival was performed using the logrank test. Analysis of S. aureus cfu/gm was by KruskalWallis non-parametric ANOVA (P<0.0001 for overall effect of serum given). P values for pairwise comparisons are shown on graph by Dunns multiple comparisons test. Transfer of antisera from mQPNAG immunized rabbits to mice C provided significant protection to mice against the lethal challenges by MRSA strain 1058 (n=10 per group); statistical analysis for survival was performed using the logrank test; and D reduced bacterial count in mouse kidneys. Sera from mQPNAG26 immunized rabbits provided the highest protection to mice. The horizontal line represents the median value of each group. Statistical analysis for survival was performed using the logrank test. Analysis of MRSA cfu/gm was by KruskalWallis non-parametric ANOVA (P=0.0967). P values for pairwise comparisons are shown on graph by Dunns multiple comparisons test. Source data are provided as a Source Data file.

Mice receiving sera from mQPNAG26 and mQPNAG10 immunized rabbits showed higher survival rates than those receiving PNAG0 sera (Fig.10A) (60% and 50%, respectively, vs 30%) and lower pathogen load compared to mQPNAG0 sera supporting the in vitro opsonic killing data (Fig.10B). We next tested the combination of two sera. Interestingly, administering the mixed PNAG26 and PNAG0 sera (1:1 ratio with each individual serum diluted 1600 times, which is regarded equivalent in concentration to 1:800 dilution of a single serum) provided 100% protection to mice against the 10*LD50 challenges with S. aureus (Fig.10A). The kidneys of mice receiving the combination of PNAG26 and PNAG0 sera had no detectable bacteria (Fig.10B). The higher protective efficacy observed with the combined sera was presumably because the PNAG polysaccharide can be heterogenous in the amine/acetylation patterns. While some of the sequences such as the fully deacetylated PNAG0 may be rare within the native PNAG polysaccharide, antibodies generated by mQPNAG0 can complement those by mQPNAG26. Thus, the combination of two mQPNAG constructs can broaden bacterial recognition and enhance protection against bacterial challenges.

The emergence of MRSA is a pressing public health concern40. Effective vaccines can provide a complementary tool to combat S. aureus infections and reduce the reliance on antibiotics. The post-immune rabbit sera were tested against multiple MRSA strains including six clinical strains first via immunofluorescent staining (Supplementary Fig.5B and Supplementary Table1). All three mQPNAG sera recognized the seven strains tested highlighting the breadth of immune recognition. A control strain lacking PNAG expression with icaA gene knock out (954) showed negligible binding by the immune sera, indicating the recognition is PNAG dependent. Next, rabbit sera were diluted 800 times and administered to mice, which were then challenged with 10*LD50 (200 million cells) of the MRSA strain 1058 via the tail vein (Fig.10C). Sera from mQPNAG26 immunized rabbits protected 90% of the mice from MRSA-induced death, which was significantly higher than the 40% protection by mQPNAG0 sera. Correspondingly, mice receiving mQPNAG26 rabbit sera had the lowest overall bacterial load in the kidneys of challenged mice (Fig.10D).

As PNAG is expressed in many types of bacteria, we explored the effects of immunization on gut microbiome. To analyze the composition of the gut microbiome, mice were fully immunized with mQPNAG26, and feces were collected on day 0 prior to immunization and day 35 following the initial prime immunization. The microbial species present in the droppings were analyzed via the 16S rRNA sequencing. Despite the significant amounts of anti-PNAG IgG produced in mouse sera, there were no significant changes in the microbial community present in the mouse gut (Supplementary Fig.8). Similar results were reported in a sponsored trial of the 5GlcNH2TT vaccine and shown in the study of anti-PNAG therapy in the setting of graft-versus-host disease41, or in human subjects in phase 1 clinical trials of both the 5GlcNH2TT vaccine or anti-PNAG mAb42,43. These observations corroborate that immunity to PNAG does not significantly alter the gut microbiome in immunized animals highlighting the potential safety of the vaccine.

In summary, numerous pathogens produce PNAG, rendering it a highly attractive target for vaccine development with the conjugate of fully deacetylated PNAG pentasaccharide with TT carrier currently undergoing human clinical trials as an anti-microbial vaccine. In order to enhance the potential protective efficacy, several aspects of the PNAG-based vaccine can be improved. As carbohydrates are typically T cell independent B cell antigens, an immunogenic carrier is critical. We have demonstrated that mQ is a powerful carrier. The mQPNAG conjugate was found to be superior in inducing higher levels of anti-PNAG IgG antibodies as compared to the corresponding PNAG conjugate with the TTHc carrier.

Besides the carrier, another important factor in vaccine design is the identification of the protective epitope(s) of the PNAG antigen, which was hampered by the lack of diverse structurally well-defined PNAG compounds. To gain a deeper understanding of the epitope specificity, a comprehensive library of PNAG pentasaccharides covering all possible combinations of free amine and NHAc has been synthesized. The synthesis is highlighted by a divergent design through the judicious choice of four amine protective groups, which can be orthogonally removed without affecting each other. The library of 32 PNAG pentasaccharides was obtained from just two strategically protected pentasaccharide intermediates, thus significantly enhancing the overall synthetic efficiency.

The availability of the comprehensive library provided an exciting opportunity to probe the epitope specificity through a glycan microarray. Screening of an anti-PNAG mAb F598 on the microarray suggests that the NHAc at unit B plays a critical role in F598 binding. NHAc at unit D could further enhance the binding. This knowledge led to the addition of two PNAG sequences (PNAG10 and PNAG26) beyond the fully deacetylated PNAG0 for vaccine studies.

The mQ conjugates with PNAG10 and PNAG26 were found to elicit IgG antibodies capable of inducing high levels of complement deposition and opsonic killing of bacteria compared to the mQPNAG0 conjugate. Vaccination with mQPNAG conjugate provided effective protection to mice against lethal challenges by S. aureus in both active and passive immunity models. Mice were also effectively protected from MRSA-induced death by the immune sera with significantly reduced bacterial load in the kidneys. The vaccines are biocompatible with no adverse side effects and do not significantly disturb the gut microbiome of the immunized mice. PNAG-based vaccine design guided by the well-defined synthetic library of PNAG is a powerful strategy to develop the next generation of vaccines and more effectively fight against pathogen infections including those by drug resistant strains.

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