COVID VACCINATION #4 aka SECOND BOOSTER…YES OR NO?

Other countries are/have been giving fourth doses of the COVID vaccine for a few months now. Two days ago (the 29th), the FDA released its own approval for a fourth COVID vaccine dose, determining that the known and potential benefits of a fourth dose outweigh any known or potential risks. Following the FDA approval, the CDC changed its guidelines as follows:

· A fourth dose of Pfizer or Moderna COVID-19 vaccine may be given to anyone 50 yo or older, at least 4 months after their third dose.

· A fourth dose is recommended for those 12-49 years of age who are immunocompromised.

What does the data really say? In looking at studies from the other countries currently offering a fourth vaccine dose, it appears to have a meaningful impact on older (60+) adults – rates of infection were 2 time lower, and the rate of severe disease was 4 times lower. HOWEVER, among younger, healthier adults, while a fourth dose increased antibody levels there appears to be no additional benefit from a clinical standpoint (in other words, no additional efficacy). Obviously, this is all preliminary data and as with anything COVID related, is subject to change as we learn more.

Other recent findings of note:

· If you had a booster and also got COVID, you likely have “hybrid immunity” which can mean antibody levels that are 25-100 times higher than with vaccines alone. Some studies suggest that this immunity can last up to a year. Does this mean you should try to get infected in order to have increased immunity later? No! The risk of long-term COVID symptoms still exists, even with only mild disease.

· When the 3rd shot was recommended, we said that it was safe to “mix and match” the Pfizer and Moderna vaccines. Now, I recommend doing so. A study released yesterday shows that there are subtle differences in the way they impact immunity. Therefore, you may get greater immunity by mixing doses. If you previously had all Pfizer vaccines, consider getting Moderna for your next shot, and vice versa.

· Recent studies showed that the J&J shot plus one mRNA shot is not quite as effective as the mRNA series. Therefore, the CDC is now recommending that all those that got the J&J vaccine plus one mRNA shot get a second mRNA vaccine if it has been 4 months since your last.

My Take Home Messages:

· In all studies, the third dose is critical. Just like the second dose was needed to protect against Delta, the third dose is just as important in protecting against Omicron. IF YOU HAVE NOT YET GOTTEN YOUR 3RD DOSE, PLEASE DO SO NOW!

· If you are 60 yo and older, the data supports getting a fourth COVID vaccine if it has been at least 4 months since your last dose.

· If you are 50-59 yo and you have other risk factors that would place you at higher risk if you were to get infected, or if you are planning on traveling this summer (especially internationally – no one wants to get sick and quarantined in another country!), I recommend getting the fourth vaccine. If you are 50-59 yo and healthy, I would keep it on your to-do list, but consider waiting until closer to the fall.

· If you are currently fully vaccinated (2 doses plus booster) and have had proven COVID within the past 6 months or so (meaning a positive test, not just symptoms), consider waiting on the 4th vaccine for now.

Brief Update on the Variants:

Deltacron: Initially identified in February, this strain has features of both Delta and Omicron. It does not seem to be a significant threat, at least at this time.

Omicron BA.2: This Omicron subvariant has 8 mutations not found on the original Omicron variant, BA.1. Globally, BA.2 is the cause of over 80% of current COVID-19 cases, and it is now the dominant strain in the US as well. Amazingly, it spreads 75% faster than the original Omicron but fortunately, it does not appear to cause severe disease. Other countries are seeing an increase of cases again, but it’s hard to say if that’s due to the BA.2 variant, or because mask mandates and other precautions have been lifted in recent weeks. It’s too soon to say whether or not BA.2 will cause significant numbers in the US.

Dr. Husney