Category: Covid-19

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FDA increases control over laboratory-developed tests after COVID-19 fiasco - Washington Examiner

The idea that SARS-CoV-2, the virus behind COVID-19, may be able to persist in the body long after the initial symptoms have faded has captivated scientists, especially those researching long COVID. A recent study has added another piece to this puzzle by demonstrating the persistence of viral proteins in blood plasma samples for up to 14 months after the initial infection.

The research team obtained samples of frozen plasma from 171 adults who had been recruited for a study back in 2020. The vast majority were people whod been infected early in the pandemic before vaccines against COVID-19 were a thing. Their samples were compared with plasma from 250 people collected pre-2020, in the halcyon days before COVID-19 entered our lives (remember those?).

The detection platform was set up to look for signals from three SARS-CoV-2 antigens: the S1 surface protein, the nucleocapsid protein, and the spike protein.

In total, 660 specimens from the pandemic group were tested, covering timepoints of 3-6 months, 6-10 months, and 10-14 months after their original COVID-19 infections. Of the individuals within the group, 25 percent had one or more detectable antigens in at least one of their samples. The most frequently detected was the spike protein, followed by S1 and nucleocapsid, which had similar frequencies to each other.

Patients who had been hospitalized when they originally had COVID-19 were almost twice as likely to have antigens present. Among those who did not receive hospital treatment, the people who self-reported worse health were also more likely to have positive antigen detection, suggesting a correlation with the severity of the acute phase of COVID.

Linking their results with those from another study, which found replication-competent virus particles i.e. virus that could still grow and infect cells in the blood of a woman who had recently died from COVID, the authors write that their findings suggest that SARS-CoV-2 might seed distal sites through the bloodstream and establish protected reservoirs in some sites.

Alternatively, they suggest, it could be that those with more severe infections got a heftier dose of virus in the first place, meaning there was more of it around to potentially evade the immune system for longer.

"The thing that I find so compelling about the data in this study is that there is a pretty striking relationship between how sick people were during their acute COVID infection and how likely they were to have evidence of antigen persistence," first author Dr Michael Peluso told Psychology Today.

"To a clinician like me, that is very convincing, because intuitively, it makes sense that people who perhaps have a higher burden of virus upfront would be more likely to have a virus that sticks around."

In an appendix to their work, the authors detail several limitations of the study. Since the majority of the patients were infected before we had vaccines and antiviral treatmentsfor the virus, its unclear whether these same results would be seen in people who caught COVID later on. Its also possible some of the participants got reinfected with COVID without knowing, meaning that some of the antigen signals could be from later infections.

However, the question of whether persistent SARS-CoV-2 may be related to either long COVID or complications later down the line remains an important one.

[O]ur data provide strong evidence that SARS-CoV-2, in some form or location, persists for up to 14 months following acute SARS-CoV-2 infection, the authors conclude. This persistence is influenced by the events of acute infection. These findings motivate an urgent research agenda regarding the clinical manifestations of SARS-CoV-2 persistence, specifically whether it is causally related to either post-acute chronic symptoms [...] or discrete incident complications.

The study is published in The Lancet Infectious Diseases.

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COVID-19 Proteins Can Hang Around In The Blood For Up To 14 Months After Infection - IFLScience

LOS ANGELES -- On a recent afternoon, Grant Oh zigzagged across the University of Southern California campus as if he was conquering an obstacle course, coming up against police blockade after police blockade on his way to his apartment while officers arrested demonstrators protesting the Israel-Hamas war.

In many ways, the chaotic moment was the culmination of a college life that started amid the coronavirus pandemic and has been marked by continual upheaval in what has become a constant battle for normalcy. Oh already missed his prom and his high school graduation as COVID-19 surged in 2020. He started college with online classes. Now the 20-year-old will add another missed milestone to his life: USC has canceled its main commencement ceremony that was expected to be attended by 65,000 people.

His only graduation ceremony was in middle school and there were no caps and gowns.

Its crazy because I remember starting freshman year with the start of the Russian invasion of Ukraine, which came after senior year of high school when the Black Lives Matter protests were happening and COVID, and xenophobia, he said It feels definitely surreal. It still shocks me that we live in a world that is so fired up and so willing to tear itself apart.

Oh, who is getting a degree in health promotion and disease prevention, added that his loss of a memorable moment pales in comparison to what is happening: At the end of the day, people are dying.

College campuses have always been a hotbed for protests from the civil rights era to the Vietnam war to demonstrations over apartheid in South Africa. But students today also carry additional stresses from having lived through the isolation and fear from the pandemic, and the daily influence of social media that amplifies the worlds wrongs like never before, experts say.

Its not just about missed milestones. Study after study shows Generation Z suffers from much higher rates of anxiety and depression than Millennials, said Jean Twenge, a psychologist and professor at San Diego State University, who wrote a book called Generations. She attributes much of that to the fact that negativity spreads faster and wider on social media than positive posts.

Gen Z, they tend to be much more pessimistic than Millennials," she said. "The question going forward is do they take this pessimism and turn it into concrete action and change, or do they turn it into annihilation and chaos?

Protesters have pitched tents on campuses from Harvard and MIT to Stanford and the University of Texas, Austin, raising tensions as many schools prepare for spring commencements. Hundreds of students have been arrested across the country. Inspired by demonstrations at Columbia University, students at more than a dozen U.S. colleges have formed pro-Palestinian encampments and pledged to stay put until their demands are met.

The campus will be closed for the semester at California State Polytechnic University, Humboldt, which has been negotiating with students who have been barricaded inside a campus building since Monday, rebuffing an attempt by the police to clear them out.

USC announced Thursday that it would be calling off its main graduation ceremony after protests erupted over not only the Israel-Hamas war but the school's decision earlier this month to call off the commencement speech by its valedictorian Asna Tabassum, who expressed support for Palestinians. Officials cited security concerns.

By trying to silence Asna, it made everything way worse, Oh said, adding that he hopes there will be no violence on graduation day May 10 when smaller ceremonies will be held by different departments.

Maurielle McGarvey graduated from high school in 2019 so was able to have a ceremony but then she took a gap year when many universities held classes only online. McGarvey, who is getting a degree in screenwriting with a minor in gender and social justice studies at USC, called the cancellations heartbreaking, and said the situation has been grossly mishandled by the university. She said police with batons came at her yelling as she held a banner while she and fellow demonstrators said a Jewish prayer.

It's definitely been like an overall diminished experience and to take away like the last sort of like typical thing that this class was allowed after having so many weird restrictions, so many customs and traditions changed, she said. Its such a bummer.

She said the email by the university announcing the cancellation particularly stung with its link to photos of past graduates in gowns tossing up their caps and cheering. That's just insult to injury," she said.

Students at other universities were equally glum.

Our grade is cursed, said Abbie Barkan of Atlanta, 21, who is graduating from the University of Texas in two weeks with a journalism degree and who was among a group of Jewish students waving flags and chanting at a counter-protest Thursday near a pro-Palestinian demonstration on campus.

University of Minnesota senior Sarah Dawley, who participated in pro-Palestinian protests, is grateful graduation plans have not changed at her school. But she said the past weeks have left her with a mix of emotions. She's been dismayed to watch colleges call in police.

But she said she also feels hope after having gone through the pandemic and become part of a community that stands up for what they believe in.

I think a lot of people are going to go on to do cool things because after all this, we care a lot, she said.

____

Watson reported from San Diego. AP journalists Stefanie Dazio and Eugene Garcia in Los Angeles, Mark Vancleave in Minneapolis, Jim Vertuno and Acacia Coronado in Austin, Texas, and Rodrique Ngowi in Boston contributed to this report.

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Class of 2024 reflects on college years marked by COVID-19, protests and life's lost milestones - ABC News

NEW YORK -- Vicky Dennis was hospitalized with strange symptoms after contracting COVID-19 in 2020. She described itchy skin, yellowing of her skin and dark urine.

In the hospital, doctors discovered Dennis was living with undiagnosed, life-threatening diseases: autoimmune hepatitis and primary biliary cholangitis.

Dennis, who was 27 years old at the time, was told she needed a liver transplant within the next five years to survive.

"You feel frozen, like you can't move forward with your life because you know the only way forward is to get this new organ," she said.

Enter Zo Johnson, who knew Dennis for years since their partners were childhood friends.

They grew infinitely closer when Johnson found out she was a match and could donate part of her liver to save Dennis.

"I was just excited at the idea that I could help somebody. I'm very, very lucky that I've always had good health and I've always had a lot of family support," Johnson said.

Dennis and Johnson underwent operations at New York-Presbyterian/Weill Cornell Medical Centerin December 2023. Johnson's surgery was done robotically, a new technique to minimize the size of the incision.

"We do it minimally invasive with laparoscopic or robotic surgery. We do everything through very small incisions, but we're taking up to 70% of the liver, and that takes time to recover," said Dr. Juan Pablo Rocca, their surgeon.

During the surgery, a portion of the donor's liver is removed and placed into the recipient. Eventually, the liver regenerates inside both patients. Essentially, surgeons use one liver to create another.

The procedure has been around for decades, but is becoming more common. New York-Presbyterian Hospital said it has completed more than 500 living liver transplants. The liver is the only organ that can regenerate itself, according to medical experts.

Data from theUnited Network for Organ Sharingsays the U.S. set a world record with more than 10,000 liver transplants performed in 2023. Six percent involved living donors.

"Any time a living donor donates a liver, there's an extra liver for someone else," said Rocca.

Dennis and Johnson have used their Instagram account to share their story since the surgery. They wear matching liver shirts, dress up as a giant liver for Halloween, and make liver-shaped cakes and stuffed toys.

"Kind of amazingly, they cleared me to exercise a month and a half after the surgery. And I ran a half marathon, the New York City Half Marathon, four months after," said Johnson, an avid runner.

At her last visit, Johnson said doctors reported more than 85% of her liver had regenerated and was functioning normally again.

"To do that for someone, it can be a very scary thing. It's not an easy operation by any means. So I think it just goes to show how incredible of a person she is," said Dennis.

While the women are still on their journeys to health, they joined a sports league and are training together to run a marathon for organ donation next year.

The United Network of Organ Sharing said more than 10,000 patients are waiting for a life-saving liver transplant and there is a massive shortage of donors.

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COVID patient's strange symptoms save her from deadly undiagnosed diseases. Here's what doctors discovered. - CBS New York

AMA Update covers a range of health care topics affecting the lives of physicians, residents, medical students and patients. From private practice and health system leaders to scientists and public health officials, hear from the experts inmedicine on COVID-19, medical education, advocacy issues, burnout, vaccines and more.

Featured topic and speakers

What causes long COVID? Is long COVID dangerous? Who is most likely to get long COVID? Any pediatric long COVID news? What can be done for long term COVID?

Our guest is Akiko Iwasaki, PhD, Sterling Professor of Immunobiology at Yale University. AMA Chief Experience Officer Todd Unger hosts.

Transcript will be posted when available.

Disclaimer: The viewpoints expressed in this video are those of the participants and/or do not necessarily reflect the views and policies of the AMA.

Get videos with expert opinions from the AMA on the most important health care topics affecting physicians, residents, medical students and patientsdelivered to your inbox.

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Akiko Iwasaki on what causes long COVID, brain fog, the Yale Paxlovid study and long COVID treatments - American Medical Association

WHO Clarifies What It Means for Disease to Spread Through the Air

International health experts have agreed on a new definition of what it means for a disease to spread through the air.

The agreement came after the World Health Organization (WHO) cooperated with hundreds of international health experts to explain or clarify the meaning. The WHO said the technical document it issued was the first step towards finding better methods to prevent airborne disease spread.

The document says the term "through the air" can be used for infectious diseases in which the main spread involves a pathogen traveling through the air or being suspended in the air. The experts said this is similar to the official description of "waterborne" diseases.

The WHOs new explanation is an effort to avoid public misunderstandings about how some diseases can be passed through the air or are airborne.

Such misunderstandings happened during the COVID-19 pandemic. The WHO was criticized by many scientists during the early days of COVID-19 in 2020. They accused the U.N. health agency of failing to warn the public early on that the virus could spread through the air.

The scientists said this led to too much public guidance centered on handwashing and similar measures to prevent the spread of COVID-19. They said this guidance ignored other measures, such as looking at the spread of viruses through ventilation systems.

By July 2020, the agency said there was "evidence emerging" of airborne spread. Soumya Swaminathan was WHO chief scientist during the start of the COVID-19 pandemic. Swaminathan began a process to agree on a new definition for airborne disease spread. She later said she thinks the agency should have been more forceful in that message "much earlier."

Swaminathans successor, Jeremy Farrar, recently told Reuters news agency the new definition was about more than COVID-19. He added that at the beginning of the pandemic there was a lack of available evidence. He said experts including the WHO had acted in "good faith." At the time, he headed the Wellcome Trust charity and advised the British government on COVID-19.

Farrar said the new definition would permit discussions to begin about issues such as ventilation in different kinds of buildings including hospitals and schools. He compared the issue to the realization that blood-borne viruses, like HIV or hepatitis B, could be spread by medics not wearing gloves.

"When I started out, medical students, nurses, doctors, none of us wore gloves to take blood," Farrar said. "Now it is unthinkable that you wouldnt wear gloves. But that came because everyone agreed on what the issue was, they agreed on the terminology [The change, in practice,] came later," he added.

Im Bryan Lynn.

Reuters reported this story. Bryan Lynn adapted the report for VOA Learning English.

____________________________________________

pathogen n. a small organism, such as a virus or a bacterium that can cause disease

ventilation n. the movement of air around a closed space, or a system that provides this

emerge v. to appear by coming out of something or out from behind something

charity n. an official organization that gives money, food and other assistance to people who need it

gloves n. a cloth or latex covering worn over the hands to protect them

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WHO Clarifies What It Means for Disease to Spread Through the Air - VOA Learning English

LOS ANGELES (AP) On a recent afternoon, Grant Oh zigzagged across the University of Southern California campus as if he was conquering an obstacle course, coming up against police blockade after police blockade on his way to his apartment while officers arrested demonstrators protesting the Israel-Hamas war.

In many ways, the chaotic moment was the culmination of a college life that started amid the coronavirus pandemic and has been marked by continual upheaval in what has become a constant battle for normalcy. Oh already missed his prom and his high school graduation as COVID-19 surged in 2020. He started college with online classes. Now the 20-year-old will add another missed milestone to his life: USC has canceled its main commencement ceremony that was expected to be attended by 65,000 people.

His only graduation ceremony was in middle school and there were no caps and gowns.

Its crazy because I remember starting freshman year with the start of the Russian invasion of Ukraine, which came after senior year of high school when the Black Lives Matter protests were happening and COVID, and xenophobia, he said It feels definitely surreal. It still shocks me that we live in a world that is so fired up and so willing to tear itself apart.

Oh, who is getting a degree in health promotion and disease prevention, added that his loss of a memorable moment pales in comparison to what is happening: At the end of the day, people are dying.

College campuses have always been a hotbed for protests from the civil rights era to the Vietnam war to demonstrations over apartheid in South Africa. But students today also carry additional stresses from having lived through the isolation and fear from the pandemic, and the daily influence of social media that amplifies the worlds wrongs like never before, experts say.

Its not just about missed milestones. Study after study shows Generation Z suffers from much higher rates of anxiety and depression than Millennials, said Jean Twenge, a psychologist and professor at San Diego State University, who wrote a book called Generations. She attributes much of that to the fact that negativity spreads faster and wider on social media than positive posts.

Gen Z, they tend to be much more pessimistic than Millennials," she said. "The question going forward is do they take this pessimism and turn it into concrete action and change, or do they turn it into annihilation and chaos?

Protesters have pitched tents on campuses from Harvard and MIT to Stanford and the University of Texas, Austin, raising tensions as many schools prepare for spring commencements. Hundreds of students have been arrested across the country. Inspired by demonstrations at Columbia University, students at more than a dozen U.S. colleges have formed pro-Palestinian encampments and pledged to stay put until their demands are met.

The campus will be closed for the semester at California State Polytechnic University, Humboldt, which has been negotiating with students who have been barricaded inside a campus building since Monday, rebuffing an attempt by the police to clear them out.

USC announced Thursday that it would be calling off its main graduation ceremony after protests erupted over not only the Israel-Hamas war but the school's decision earlier this month to call off the commencement speech by its valedictorian Asna Tabassum, who expressed support for Palestinians. Officials cited security concerns.

By trying to silence Asna, it made everything way worse, Oh said, adding that he hopes there will be no violence on graduation day May 10 when smaller ceremonies will be held by different departments.

Maurielle McGarvey graduated from high school in 2019 so was able to have a ceremony but then she took a gap year when many universities held classes only online. McGarvey, who is getting a degree in screenwriting with a minor in gender and social justice studies at USC, called the cancellations heartbreaking, and said the situation has been grossly mishandled by the university. She said police with batons came at her yelling as she held a banner while she and fellow demonstrators said a Jewish prayer.

It's definitely been like an overall diminished experience and to take away like the last sort of like typical thing that this class was allowed after having so many weird restrictions, so many customs and traditions changed, she said. Its such a bummer.

She said the email by the university announcing the cancellation particularly stung with its link to photos of past graduates in gowns tossing up their caps and cheering. That's just insult to injury," she said.

Students at other universities were equally glum.

Our grade is cursed, said Abbie Barkan of Atlanta, 21, who is graduating from the University of Texas in two weeks with a journalism degree and who was among a group of Jewish students waving flags and chanting at a counter-protest Thursday near a pro-Palestinian demonstration on campus.

University of Minnesota senior Sarah Dawley, who participated in pro-Palestinian protests, is grateful graduation plans have not changed at her school. But she said the past weeks have left her with a mix of emotions. She's been dismayed to watch colleges call in police.

But she said she also feels hope after having gone through the pandemic and become part of a community that stands up for what they believe in.

I think a lot of people are going to go on to do cool things because after all this, we care a lot, she said.

Watson reported from San Diego. AP journalists Stefanie Dazio and Eugene Garcia in Los Angeles, Mark Vancleave in Minneapolis, Jim Vertuno and Acacia Coronado in Austin, Texas, and Rodrique Ngowi in Boston contributed to this report.

More:

Class of 2024 reflects on college years marked by COVID-19, protests and life's lost milestones - Mcalester News Capital

Antonio Guillem / iStock

Sense of smellbut not tastewas still impaired in some COVID patients at 1 year, according to a new study in JAMA Network Open.

The US-based cross-sectional study compared 340 people with and 434 without prior COVID-19, recruited from February 2020 to August 2023 from the social media website Reddit.

Researchers instructed participants to take the 53-item Waterless Empirical Taste Test (WETT) and 40-item University of Pennsylvania Smell Identification Test (UPSIT) to assess taste and smell function.

Loss of taste and smell was one of the first symptoms most commonly ascribed to COVID-19 infections, but few studies have looked at the loss after 1 year, or in infections caused by newer variants. Furthermore, only a handful of studies have been based on smell and taste tests.

Participants in the study had a mean time between testing and COVID-19 diagnosis of 395 days (95% confidence interval [CI], 363 to 425 days). The total WETT scores did not differ significantly between participants with and without a COVID-19 history, with both groups falling within normal ranges.

The UPSIT test assessing smell, however, showed that people with COVID-19 had mean scores that were significantly lower than those without a history of COVID (age- and sex-adjusted mean, 34.4 [95% CI, 33.9 to 34.9] compared to 35.9 [95% CI, 35.4 to 36.3], a 4.2% reduction.

Participants with a history of COVID-19 were more likely to experience some degree of smell loss compared with those without a history (30.3% vs 21.0%; odds ratio [OR], 1.64; 95% confidence interval [CI], 1.18 to 2.27). Moderate to severe loss of smell was likewise higher in those with previous COVID-19 (8.5% vs 2.8%; OR, 3.28; 95% CI, 1.65 to 6.53).

Reports that taste loss continues long after the initial infection probably are due in large part to the confusion between taste- and olfaction-dependent food flavor.

"Reports that taste loss continues long after the initial infection probably are due in large part to the confusion between taste- and olfaction-dependent food flavor," the authors explained. "Smell loss remained in nearly one-third of individuals with exposure, likely explaining taste complaints of many individuals with [long COVID]."

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Impaired sense of smell still common 1 year after COVID-19 - University of Minnesota Twin Cities

Sarah E. Smith-Jeffcoat, MPH1; Alexandra M. Mellis, PhD2; Carlos G. Grijalva, MD3; H. Keipp Talbot, MD3; Jonathan Schmitz, MD, PhD3; Karen Lutrick, PhD4; Katherine D. Ellingson, PhD4; Melissa S. Stockwell, MD5,6,7; Son H. McLaren, MD8; Huong Q. Nguyen, PhD9; Suchitra Rao, MBBS10; Edwin J. Asturias, MD10; Meredith E. Davis-Gardner, PhD11; Mehul S. Suthar, PhD11; Hannah L. Kirking, MD1; RVTN-Sentinel Study Group (View author affiliations)

What is already known about this topic?

During the COVID-19 pandemic, rapid antigen tests were found to detect potentially transmissible SARS-CoV-2 infection, but antigen tests were less sensitive than reverse transcriptionpolymerase chain reaction (RT-PCR) testing.

What is added by this report?

During November 2022May 2023, among persons infected with SARS-CoV-2, sensitivity of rapid antigen tests was 47% compared with RT-PCR and 80% compared with viral culture. Antigen tests continue to detect potentially transmissible infection but miss many infections identified by positive RT-PCR test results.

What are the implications for public health practice?

Rapid antigen tests can aid in identifying infectiousness of persons infected with SARS-CoV-2 and providing access to diagnostic testing for persons with COVID-19 symptoms. Persons in the community eligible for antiviral treatment should seek more sensitive diagnostic tests from a health care provider. Clinicians should consider RT-PCR testing for persons for whom antiviral treatment is recommended.

As population immunity to SARS-CoV-2 evolves and new variants emerge, the role and accuracy of antigen tests remain active questions. To describe recent test performance, the detection of SARS-CoV-2 by antigen testing was compared with that by reverse transcriptionpolymerase chain reaction (RT-PCR) and viral culture testing during November 2022May 2023. Participants who were enrolled in a household transmission study completed daily symptom diaries and collected two nasal swabs (tested for SARS-CoV-2 via RT-PCR, culture, and antigen tests) each day for 10 days after enrollment. Among participants with SARS-CoV-2 infection, the percentages of positive antigen, RT-PCR, and culture results were calculated each day from the onset of symptoms or, in asymptomatic persons, from the date of the first positive test result. Antigen test sensitivity was calculated using RT-PCR and viral culture as references. The peak percentage of positive antigen (59.0%) and RT-PCR (83.0%) results occurred 3 days after onset, and the peak percentage of positive culture results (52%) occurred 2 days after onset. The sensitivity of antigen tests was 47% (95% CI=44%50%) and 80% (95% CI=76%85%) using RT-PCR and culture, respectively, as references. Clinicians should be aware of the lower sensitivity of antigen testing compared with RT-PCR, which might lead to false-negative results. This finding has implications for timely initiation of SARS-CoV-2 antiviral treatment, when early diagnosis is essential; clinicians should consider RT-PCR for persons for whom antiviral treatment is recommended. Persons in the community who are at high risk for severe COVID-19 illness and eligible for antiviral treatment should seek testing from health care providers with the goal of obtaining a more sensitive diagnostic test than antigen tests (i.e., an RT-PCR test).

SARS-CoV-2 rapid antigen tests were developed and received Food and Drug Administration Emergency Use Authorization early during the COVID-19 pandemic.* These tests were initially rolled out broadly in the United States to diagnose cases and isolate persons who received positive test results to aid in preventing onward spread at a time when population SARS-CoV-2 immunity was low, and rates of severe COVID-19associated outcomes were high. In addition, demands for testing exceeded supply, and long turnaround times for reverse transcriptionpolymerase chain reaction (RT-PCR) test results contributed to ongoing transmission. Wide access to antigen tests was made possible through U.S. government initiatives implemented to prevent transmission., After the emergence of the Omicron variant in late 2021, at-home antigen test use began to increase sharply (1,2).

Studies conducted during circulation of SARS-CoV-2 pre-Delta and Delta variants illustrated that antigen tests have high specificity, but lower sensitivity when compared with RT-PCR tests, thereby missing a substantial number of infections but correlating more closely with viral culture results (36). Viral culture, although not frequently used for routine patient care, is able to detect actively replicating virus (thus identifying when a person is likely to be infectious), whereas RT-PCR cannot distinguish between replicating virus and viral fragments. Most of these studies included few participants with vaccine- or infection-induced immunity. SARS-CoV-2 variants and population immunity have evolved since many of the studies assessing antigen tests were performed; thus, the role that antigen tests should play in diagnosing SARS-CoV-2 infection remains an active question. The objective of this investigation was to reevaluate the performance characteristics of SARS-CoV-2 antigen tests with those of RT-PCR and viral culture tests during a period with greater population immunity and more recently circulating SARS-CoV-2 Omicron variants.

This evaluation included participants enrolled in an antigen test substudy within a case-ascertained household transmission study during November 2022May 2023 (7). Index patients with confirmed SARS-CoV-2 infection and their household contacts were enrolled within 7 days of illness onset in the index patient. Participants completed baseline surveys including demographic characteristics, COVID-19 signs or symptoms (symptoms),** vaccination, and self-reported previous infection. Participants (index patients and contacts) also provided a blood specimen for SARS-CoV-2 anti-N antibody detection (8,9). For 10 days after enrollment, all participants completed daily COVID-19 symptom diaries and collected two nasal swabs each day. One swab was self-collected in viral transport media, stored in refrigerator for up to 72 hours, then collected by a study team member and stored at 12F (80C) until aliquoted for automated RT-PCR (Hologic Panther Fusion) and viral culture,*** and the other swab was used for at-home antigen testing. Participants interpreted and reported their antigen test results in their daily symptom diary. For this analysis, SARS-CoV-2 infection was defined as at least one positive RT-PCR test result during the study period; onset was defined as the first day of symptoms or, if the participant remained asymptomatic, day of first positive test result.

Among participants who ever received a positive RT-PCR test result and had one or more paired RT-PCR and antigen results reported, the percentage of positive antigen, RT-PCR, and viral culture results was calculated for each day relative to onset. The percentage of positive antigen test results was stratified by symptom and fever status. Sensitivity of antigen testing among paired samples collected from 2 days before until 10 days after onset was computed using two references: 1) same-day positive RT-PCR result and 2) same-day positive culture result, stratified by overall symptom status and presence of fever alone or fever or cough. Wilson score intervals were used for calculating 95% CIs around percentage of positive test results. Cluster-robust bootstrapping was used to calculate 95% CIs around sensitivity to account for within-participant correlation. All analyses were performed in RStudio (version 4.2.3; RStudio). This study was reviewed and approved by the Vanderbilt University Institutional Review Board.

Among 354 participants in 129 households, 236 (67%) received a positive SARS-CoV-2 RT-PCR test result and were included in this investigation (Table). Participants ranged in age from 2 months to 83 years (median=36 years; IQR=1750 years), 133 (56%) were non-Hispanic White persons, and 140 (59%) were female. Ninety-two (40%) participants reported receipt of a COVID-19 vaccine 12 months before enrollment; 82 (35%) had received 2 doses, but the most recent dose was >12 months before enrollment; 57 (24%) were unvaccinated (including those who had only ever received 1 dose); and vaccination status was unknown for five participants. A total of 102 (43%) participants had self-reported or serologic evidence of previous SARS-CoV-2 infection. At least one COVID-19 symptom was reported by 219 (93%) participants, including 182 (77%) who reported cough and 156 (66%) who reported fever.

Among the 236 SARS-CoV-2infected participants (i.e., those who received a positive RT-PCR test result), 2,244 antigen results were reported and included in analyses. Overall, 143 (61%) participants received one or more positive culture result, and 164 (69%) received one or more positive antigen test result.

The highest percentage of positive antigen (59%; 95% CI=51%67%) and RT-PCR (83%; 95% CI=76%88%) test results occurred 3 days after onset (Figure 1). The highest percentage of positive viral culture results (52%; 95% CI=43%61%) occurred 2 days after onset. Among the 219 symptomatic participants, the highest percentage of positive antigen test results was 65% (95% CI=57%73%) at 3 days after onset among those who experienced any COVID-19 symptom and 80% (95% CI=68%88%) at 2 days after onset among those who reported fever.

Compared with same-day collected RT-PCR and culture results, the overall sensitivities of daily antigen test results were 47% (95% CI=44%50%) and 80% (95% CI=76%85%), respectively (Figure 2) (Supplementary Table, https://stacks.cdc.gov/view/cdc/153544). When stratified by symptoms experienced on the day of specimen collection, antigen test sensitivity increased with occurrence of any COVID-19 symptoms (56% and 85% compared with RT-PCR and culture, respectively) and peaked on days that fever was reported (77% and 94% compared with RT-PCR and culture, respectively). Compared with RT-PCR and culture results, sensitivity of antigen testing was low on days when no symptoms were reported (18% and 45%, respectively).

Among participants enrolled in a household transmission study during a period of increased disease- and vaccine-induced immunity, and when circulating viruses differed antigenically from the ancestral SARS-CoV-2 strain, antigen and culture tests detected a similar proportion of SARS-CoV-2 infections, but detection by RT-PCR was higher than that by either antigen or culture. Similarly, paired antigen test sensitivity was low compared with RT-PCR (47%), but relatively high compared with culture (80%). The sensitivity of antigen testing was higher when symptoms were present on the test day and peaked on days when participants reported fever. Although viral culture is not an absolute marker of transmissibility, this pattern suggests that positive antigen test results could indicate transmissible virus; thus, antigen tests might aid persons with COVID-19 in determining when they are no longer infectious once symptoms begin to resolve.

The findings from this investigation remain similar to those reported in other studies throughout the COVID-19 pandemic (36). For example, considering the current studys sensitivity results, an early 2021 study comparing antigen testing with RT-PCR and culture found similar antigen test sensitivity compared with culture (84%), but slightly higher sensitivity compared with RT-PCR (64%) (3). The sensitivity difference between these two studies could be attributed to many factors, including differences in participant immunity, infecting variants, the limit of detection of the reference RT-PCR, or sampling methods.

Minimizing false negative test results is important because additional modalities, including antiviral medications, are available to prevent severe outcomes. Antiviral treatments for SARS-CoV-2 infection should be started as soon as possible, and within 57 days of symptom onset. Therefore, persons who are at higher risk for severe illness and eligible for antiviral treatment would benefit from a more accurate diagnostic test. In most clinical scenarios in the United States, this approach means a SARS-CoV-2 RT-PCR test would be a better diagnostic test to minimize the risk for a false-negative result. Alternatively, if RT-PCR tests are not available or accessible, clinicians and patients should follow FDAs serial antigen testing recommendations to help optimize diagnostic test performance.****

The findings in this report are subject to at least three limitations. First, participants included in this analysis might not represent all U.S. persons infected with SARS-CoV-2 and represent those with mild to moderate illness. These findings might not apply to persons with more severe COVID-19 illness. Second, one commercially available antigen test was used in this study; results might not apply to all available antigen tests. Finally, because of the parent study design, onset for asymptomatic participants (i.e., the day of the first positive test result), could be biased if household members were not enrolled early enough to record the earliest positive test result.

As COVID-19 becomes endemic and public focus shifts from stopping transmission to preventing severe illness, diagnostic testing should emphasize use of the best tests to identify infection in persons who would benefit from treatment. The low sensitivity of antigen testing among persons with asymptomatic infections illustrates that these tests should only be used once symptoms are present. Conversely, the higher sensitivity when symptoms are present (especially cough or fever) supports the need to stay at home when symptomatic, irrespective of test result. The low sensitivity of antigen tests compared with RT-PCR tests has implications for timely initiation of antiSARS-CoV-2 treatment when early and accurate diagnosis is important. With several treatment options available, clinicians should consider more sensitive RT-PCR tests for accurate diagnosis in persons at higher risk for severe illness to minimize delays in treatment initiation. Persons in the community who are at high risk for severe COVID-19 illness and eligible for antiviral treatment should seek testing from health care providers with the goal of obtaining a more sensitive diagnostic test than antigen tests (i.e., an RT-PCR test).

Supraja Malladi, CDC; Erica Anderson, Marcia Blair, Jorge Celedonio, Daniel Chandler, Brittany Creasman, Ryan Dalforno, Kimberly Hart, Andrea Stafford Hintz, Judy King, Christopher Lindsell, Zhouwen Liu, Samuel Massion, Rendie E. McHenry, John Meghreblian, Lauren Milner, Catalina Padilla-Azain, Bryan Peterson, Suryakala Sarilla, Brianna Schibley-Laird, Laura Short, Ruby Swaim, Afan Swan, His-nien Tan, Timothy Williams, Paige Yates, Vanderbilt University Medical Center; Hannah Berger, Brianna Breu, Gina Burbey, Leila Deering, DeeAnn Hertel, Garrett Heuer, Sarah Kopitzke, Carrie Marcis, Jennifer Meece, Vicki Moon, Jennifer Moran, Miriah Rotar, Carla Rottscheit, Elisha Stefanski, Sandy Strey, Melissa Strupp, Murdoch Childrens Research Institute; Lisa Saiman, Celibell Y Vargas, Anny L. Diaz Perez, Ana Valdez de Romero, Raul A. Silverio Francisco, Columbia University.

Melissa A. Rolfes, National Center for Immunization and Respiratory Diseases, CDC; Jessica E. Biddle, National Center for Immunization and Respiratory Diseases, CDC; Yuwei Zhu, Vanderbilt University Medical Center, Nashville, Tennessee; Karla Ledezma, University of Arizona, Tucson, Arizona; Kathleen Pryor, University of Arizona, Tucson, Arizona; Ellen Sano, Columbia University Irvin Medical Center, New York, New York; Joshua G. Petrie, Marshfield Clinic Research Institute, Marshfield, Wisconsin.

Corresponding author: Sarah E. Smith-Jeffcoat, uyi7@cdc.gov.

1Coronavirus and Other Respiratory Viruses Division, National Center for Immunization and Respiratory Diseases, CDC; 2Influenza Division, National Center for Immunization and Respiratory Diseases, CDC; 3Vanderbilt University Medical Center, Nashville, Tennessee; 4University of Arizona Colleges of Medicine and Public Health, Tucson, Arizona; 5Division of Child and Adolescent Health, Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York; 6Department of Population and Family Health, Mailman School of Public Health, New York, New York; 7New York-Presbyterian Hospital, New York, New York; 8Department of Emergency Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York; 9Marshfield Clinic Research Institute, Marshfield, Wisconsin; 10Childrens Hospital Colorado, Aurora, Colorado; 11Department of Pediatrics-Infectious Diseases, Emory Vaccine Center, Emory Primate Research Center, Emory University School of Medicine, Atlanta, Georgia.

Abbreviations: RT-PCR = reverse transcriptionpolymerase chain reaction; SVI = Social Vulnerability Index. * SARS-CoV-2 infection defined as having received at least one positive RT-PCR result during study testing. Persons of Hispanic or Latino (Hispanic) origin might be of any race but are categorized as Hispanic; all racial groups are non-Hispanic. SVI was determined using the 2020 U.S. Census Bureau decennial tract location of the home. SVI uses 16 census variables to indicate the relative vulnerability of every census tract to a hazardous event with values closer to 1 representing highly vulnerable areas and values closer to 0 representing least vulnerable areas. Vaccination history was self-reported and then verified by study team. Participants were considered vaccinated within 12 months before enrollment if they had received 2 doses and the most recent dose was received between 14 days and 12 months before enrollment; vaccinated >12 months before enrollment if they had received 2 doses and the most recent dose was received >12 months before enrollment; and unvaccinated if they received <2 doses before enrollment. ** By self-report or serologic evidence. Previous SARS-CoV-2 infection was defined as self-report of a previous infection 1 month before enrollment or by detection of antinucleocapsid antibodies from a dried blood spot collected at baseline. Elicited COVID-19 signs and symptoms included fever (including feeling feverish or chills), cough, sore throat, runny nose, nasal congestion, fatigue (including feeling run-down), wheezing, trouble breathing (including shortness of breath), chest tightness (including chest pain), loss of smell or loss of taste, headache, abdominal pain, diarrhea, vomiting, and muscle or body aches.

Abbreviation: RT-PCR = reverse transcriptionpolymerase chain reaction.

* With 95% CIs indicated by shaded areas.

Elicited COVID-19 signs and symptoms included fever (including feeling feverish or chills), cough, sore throat, runny nose, nasal congestion, fatigue (including feeling run-down), wheezing, trouble breathing (including shortness of breath), chest tightness (including chest pain), loss of smell or loss of taste, headache, abdominal pain, diarrhea, vomiting, and muscle or body aches.

Date of symptom onset or, for asymptomatic persons, date of first positive test result.

SARS-CoV-2 infection defined as having received at least one positive RT-PCR test result during study testing.

Abbreviation: RT-PCR = reverse transcriptionpolymerase chain reaction.

* With 95% CIs indicated by error bars.

Elicited COVID-19 signs and symptoms included fever (including feeling feverish or chills), cough, sore throat, runny nose, nasal congestion, fatigue (including feeling run-down), wheezing, trouble breathing (including shortness of breath), chest tightness (including chest pain), loss of smell or loss of taste, headache, abdominal pain, diarrhea, vomiting, and muscle or body aches.

Suggested citation for this article: Smith-Jeffcoat SE, Mellis AM, Grijalva CG, et al. SARS-CoV-2 Viral Shedding and Rapid Antigen Test Performance Respiratory Virus Transmission Network, November 2022May 2023. MMWR Morb Mortal Wkly Rep 2024;73:365371. DOI: http://dx.doi.org/10.15585/mmwr.mm7316a2.

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SARS-CoV-2 Viral Shedding and Rapid Antigen Test Performance Respiratory Virus Transmission Network ... - CDC

Taking the SARS-CoV-2 antiviral drug nirmatrelvir-ritonavir (Paxlovid) 3 to 5 days after COVID-19 symptom onsetnot earlier or latermay result in the greatest reduction in viral loads, viral transmission, and viral rebound in hospitalized patients, a University of Hong Kongledstudy finds.

For the study, posted by eLife, which publishes peer-reviewed preprints, the investigators fitted a mathematical model of in vivo Omicron variant behavior to electronic medical record data from 208 patients hospitalized with mild to moderate COVID-19 in Hong Kong from January to May 2022. The Omicron BA.2 variant was dominant during the study period.

Half of the patients received Paxlovid, and the other half were given no antiviral therapy. Participants were aged 8 to 103 years.

The study authors noted thatdespite the availability of antivirals within 5 miles of home for 90% of Americans through the US Test-to-Treat program, US uptake has been relatively low, with only 11% of COVID-19 patients prescribed the drugs during the study period. Paxlovid is prescribed for patients at high risk for severe disease.

"The low uptake may stem from slow rollouts in some areas, complex eligibility requirements, testing, and potential drug interactions, as well as concerns about viral rebounds following Paxlovid treatment," they wrote.

In Hong Kong, under 40% of COVID-19 patients older than 60 years had been prescribed Paxlovid by late July 2022.

"Low rates of antiviral uptake may stem from misinformation, lack of access, and the rising proportion of cases that opt for at-home rapid tests and do not seek healthcare," the researchers wrote. "Telemedicine and online healthcare services can accelerate and expand access to antivirals, but may not reach some of the older populations in Hong Kong."

In total, 62% of Paxlovid recipients started the drug 3 to 5 days after symptom onset.When the drug was started 3 days after symptom onset, the odds of post-treatment viral rebound was low (17%), with a 12% lower risk of transmission among non-rebound patients. The findings suggest thatPaxlovid can prevent over 90% of viral replication if it is given at the optimal time, the study authors said.

But if Paxlovid is initiated before 3 days, the risk of viral rebound is significantly increased with no improvement in infectiousness, with a 74% chance of viral rebound if started the day after symptom onset. And starting the drug after 5 days of symptom emergence lowers the drug's ability to stem peak viral shedding (0% reduction at 10 days).

The development of global distribution programs that provide rapid and equitable access to antivirals could enhance our ability to combat COVID-19 as the virus and the landscape of immunity continues to evolve.

"Our findings indicate that broader global access to Paxlovid, coupled with appropriately timed treatment, can mitigate the severity and transmission of SARS-CoV-2," the researchers concluded.

Giving Paxlovid to more patients may help quell future pandemic waves without the need for socioeconomically expensive lockdowns, lead author Zhanwei Du, PhD, of the World Health Organization (WHO) Collaborating Center for Infectious Disease Epidemiology and Control at the University of Hong Kong, said in an eLifepress release. "However, to get the most out of these drugs, we first need to understand the optimal timing for taking them and to encourage their wider distribution and uptake," he said.

The researchers, however, caution that their data didn't consider the potential emergence of Paxlovid resistance, which would require further research before the antiviral could be deployed more broadly.

"The development of global distribution programs that provide rapid and equitable access to antivirals could enhance our ability to combat COVID-19 as the virus and the landscape of immunity continues to evolve," they concluded.

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Data: Optimal initiation of Paxlovid in hospitalized COVID patients is 3 to 5 days - University of Minnesota Twin Cities