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  • Writer's pictureDr. Jon Kaiser

Booster Shots? The Data is Now In.


Over 90% of coronavirus hospitalizations and deaths occur in unvaccinated people. The current Covid-19 vaccines are safe and unfortunately have been underutilized.


In addition to increasing the percentage of people who get vaccinated in the first place, it’s now important to look at who might need to boost their immunity beyond the initial round of shots.

Last week a panel of 18 medical experts in the fields of virology and epidemiology met to analyze the available data and report their findings on this question as part of the FDA’s advisory panel on Covid-19 booster shots.


While the Biden administration has proposed authorizing vaccine booster shots for all individuals 8 months after their initial vaccination, experts on this panel voted for a somewhat different plan.


Question #1 – Do the safety and effectiveness data support approval of a Pfizer vaccine booster shot for all individuals, administered at least 6 months after completing the initial series?


Medical Experts -> 16-2 AGAINST


Question #2 – Do the safety and effectiveness data support approval of a Pfizer vaccine booster shot administered at least 6 months after completing the initial series for people over age 65 and those at higher risk for a severe Covid-19 infection?


Medical Experts -> 18-0 IN FAVOR


These recommendations were based on findings that antibody levels do not rise sufficiently in these populations, and then begin to decrease after six months,


The medical experts also unanimously supported a booster shot for health care workers or others at high risk of occupational coronavirus exposure.



These votes were not unexpected in public health circles and reflect an objective review of the currently available data. While studies in the US often focus on age 65 as a cutoff, studies abroad such as those performed in Israel, support using age 60 as a cutoff.


While there is a progressive drop of anti-Covid-19 antibody levels over time, your immune response includes another kind of response called cellular immunity. There is no evidence that this aspect of immunity to Covid-19 wanes.


My Recommendations


I will be recommending Covid-19 booster shots for:


1. Individuals over age 60 who are at least 6 months beyond completing their initial series.


2. Healthcare workers or others at high risk for occupational coronavirus exposure (who are at least 6 months beyond completing their initial series).


3. Individuals at increased risk for a severe Covid-19 infection including transplant patients, people taking immunosuppressive drugs, those on chemotherapy, HIV(+) patients, and other individuals with more difficult to categorize immune disorders (who are at least 6 months beyond completing their initial series).


The FDA will likely release their formal recommendations later this week.


Data for the Moderna vaccine on this issue should become available in a few weeks.


The following is a general rule for how to rate Covid-19 immunity:


Level 1 – Previous Covid infection (of any severity)


Level 2 – Vaccination


Level 3 – Vaccination + Booster shot


Level 4 – Previous Covid infection + Vaccination


Level 5 – Previous Covid infection + Vaccination + Booster shot


I hope this information has been helpful and provides some clarity in helping you make what may be a challenging personal decision.


Please forward my Blog to your family and friends.


Keep Hope Alive!

Jon D. Kaiser, M.D.

Appointments: (415) 381-7655

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