Updated COVID-19 Boosters and XBB.1.5: What You Need to Know – American Society for Microbiology

SARS-CoV-2

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Unfortunately, only 23.5% of those who were hospitalized in the U.S. had received the recommended COVID-19 bivalent vaccine, and only 58.6% had received the original vaccines rolled out at the end of 2020 and beginning of 2021. Globally, it may appear that there is a better vaccination rate achieved, with more than 5.55 billion people worldwide receiving a dose of a COVID-19 vaccine, equal to about 72.3% of the world population. However, more in-depth research reveals a stark gap exists between vaccination programs in different countries.

Source: CDC

How is the updated vaccine different from previous vaccines? Who should get vaccinated? Will the current version provide protection against recentCOVID-19 variants? When should one get vaccinated, and can other seasonal vaccinations beadministered simultaneously?

Updated COVID-19 vaccines by Pfizer-BioNTech and Moderna were approved (mid-Sept. 2023) by the Food and Drug Administration (FDA) and recommended by the CDC.The updated vaccine is, once again, a monovalent version, which was created to protect people from the Omicron XBB.1.5 subvariant. While this specific variant is currently responsible for only about 3% of all U.S. cases, the dominant variants that are currently circulating are closely related to it. In other words, the current COVID-19 virus is so close to the vaccine version that it will protect us.

Prior to mRNA vaccine development, many vaccines were created to challenge the immune system with a microbe against which theyre meant to protecteither the entire pathogen or some crucial component. Meaning, in the past the world relied on making vaccines by using weakened or inactivated versions of a virus, which would be injected into eggs (flu), humans or other host cells. This was a lengthy process, and often by the time the vaccine was available, the circulating viruses had already changed genetically, rendering the vaccines less effective.

mRNA vaccines have completely turned vaccine creation on its head. The mRNA vaccines work differently because now they present a genetic code (nucleic acid language) that human cells can translate into proteins. Thus, mRNA in the vaccine is used to prompt host cells to produce viral proteins that stimulate an immune response upon future exposure/infection to that particular pathogenusually by helping neutralize the virus with antibodies. Additionally, existing COVID-19 vaccines offer a resilient cell-mediated immune response.

The amazing power of mRNA vaccines is that the turnaround time required to produce them can be lifesaving in real time. In other words, vaccine makers can simply adapt the nucleic acid code found in the most current versions of circulating COVID-19 variants (or other viruses like the flu) to contain codes for the spike protein found jutting from the outer surface of the virus, and within weeks to a month, our bodies can be immunized to ultimately make copies of a current variants spike protein, which the immune system learns to subsequently recognize.

Source: CDC

Importantly, RNA viruses, including SARS, RSV and influenza, make it very difficult to produce a long-lasting vaccine since these viruses areconstantly evolving. In other words, SARS-CoV-2 is a moving target at the molecular level. As with flu vaccination and others, these new versions of the COVID-19 vaccine will not prevent all COVID-19 infections, but unless there is a major genetic shift in the virus, like we saw with Delta to Omicron in the winter of 2021, the current COVID-19 vaccines will offer partial-to-full protection from circulating variants.

Furthermore, these newer versions are expected to have an immediate impact for preventing severe illness, hospitalization and death from a COVID-19 infection, and the release of this vaccine is well-timed to coincide with the winter season in the Northern Hemisphere, when respiratory infections, hospitalizations and mortality rates tend to rise.

According to the CDC and WHO, the new COVID-19 vaccine should be taken in the fall, around the Sept.-Oct. timeframe (Northern Hemisphere) for best protection in the winter season. There may be a need for some individuals to receive the vaccine sooner (e.g., immunocompromised).

The COVID-19 vaccine is safe to receive at the same time as your annual influenza (e.g., flu) vaccine. The new respiratory syncytial virus (RSV) vaccine may be administered at the same time as well.

The CDC states that individuals who recently had a COVID-19 infectionmay wait up to 3 months before being vaccinated.And although experts collectively agree that people should wait until symptoms of an active COVID-19 infection resolve before getting vaccinated, there may be pros and cons to waiting for natural immunity to wane (~3 months) before boosting. On one hand, getting boosted before the 3 months have passed may produce higher levels of SARS-CoV-2 antibodies thanwhat would be produced from COVID-19 infection alone, a factorthat could make this a more desirable option, especially for those with high risk of SARS-CoV-2 exposure.However, waiting 3 months for natural immunity to wane, may generate a more robust antibody response upon boosting, which may be desirable for those who have alower risk of day-to-day exposure.

In any case, it is important to stay up to date on vaccination, as people who do not get vaccinated after recovery from COVID-19infection aremore likely to get COVID-19 againthan those who get vaccinated after their recovery.

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Updated COVID-19 Boosters and XBB.1.5: What You Need to Know - American Society for Microbiology