top of page
  • Writer's pictureWilliam Miller, MD

"Mix & Match" Booster Shots

Updated: Apr 26, 2022

Last week we discussed how the FDA is considering approving booster shots for both Moderna and J&J COVID vaccines. Booster shots for Pfizer were approved last month. It seems that this is most important for those who got the J&J one time shot, as immunity seems to be waning the fasted with J&J of the three. However, overall, it is still much more effective at preventing serious illness and death than not being vaccinated at all. The FDA is expected to grant this approval this week followed by CDC recommendations to healthcare providers.

A new and interesting development this week is that the National Institute of Health announced a study in which they looked at the effect of a booster from a different vaccine than the original series. In other words, what if you initially got the two Moderna shots, but now only the Pfizer is easily available as the booster. This study, which only looked at antibody levels in the blood and not at following subjects to see if they got infected or sick, showed a substantial boost in protective antibody levels regardless of which combination a person received. The most dramatic increase was for people who had the one-time J&J followed by a Moderna booster. This is due to the lower starting antibody levels of the J&J coupled with the strong response to the Moderna shot.

The final approval and recommendations, expected to come out this week, will likely allow healthcare providers to “mix and match” based on what they have available at the time while recommending staying with the same brand if possible. This is a good thing as it will grant flexibility so that we are not hampered by supplies on hand.

What is ultimately driving this whole booster approval is a desire to get as many people in the US to the highest possible level of immunity prior to going into the winter season with a more contagious delta variant than last year. This is a strategy to try to counter the remaining large numbers of folks who have shied away from getting vaccinated. I expect that we will be seeing a lot of them in our ERs and ICUs as the winter goes on and keeping the rest of the population who are vaccinated out of the hospital will be important so we don’t overwhelm our healthcare systems.

We continue to expect a decision soon on lowering the age limit of the vaccines to 5 and above. Currently it is set at 12 for Pfizer and 18 for the others. The FDA is scheduled to make this decision on October 26th. Related to vaccination in adolescents, the CDC’s Morbidity and Mortality Weekly Report (MMWR) reported this week on COVID cases from 12 pediatric hospitals in the US. This study looked at 179 adolescents between 12 and 18 admitted recently for COVID. It found that 173 (97%) were unvaccinated and that 77 (43%) ended up in the ICU with two deaths. None of the 6 vaccinated kids required ICU care or died.

Lastly, a note on General Colin Powell, a man that I highly respected and I think of as a great leader willing to own his mistakes and also call things as they are. As you may have heard, he passed away this week at the age of 84 of COVID related complications. The news media has placed some focus on the fact that he was fully vaccinated with Pfizer, receiving his second dose back in February. In addition to his advanced age, a risk factor in itself, he was also suffering from multiple myeloma. This is a cancer of the immune system that severely lowers a person's ability to fight off infections. While this is an interesting side note on his otherwise distinguished life, I think it is important for us to remember that we need to make decisions based on scientific studies that involve large numbers of subjects so as to eliminate natural variability and error as much as possible. Single person anecdotes are interesting, but not particularly helpful in guiding our decision making.

5 views0 comments


bottom of page