top of page
  • Writer's pictureDr. Bow Tie

COVID-19 and Vaccines: Boosters Update, Mix & Match

I just put out the flu vaccine post earlier this week and normally I let my posts stand for a bit before I do another, but there was a lot of news this week! The Food & Drug Administration's Vaccines and Related Biological Products Advisory Committee once again met to discuss boosters and delivered recommendations to the FDA as a whole, who then submitted recommendations to the Center for Disease Control's Advisory Committee on Immunizations Practices (just as they did earlier this month).

The FDA has authorized, the ACIP officially recommends, and CDC Director Rochelle Walensky has approved, booster doses of all three major American COVID vaccines. Pfizer had been previously approved earlier this month, and now Moderna and J&J have been authorized for boosters. Pfizer-BioNTech and Moderna boosters can be taken 6 months or longer after your second dose. The studied Pfizer-BioNTech booster is another full dose. The Moderna booster trials studied a half-dose booster, so that is what will be given.

ACIP & the CDC recommended that all recipients of the J&J vaccine 18+ should get a second dose of J&J at least two months after their first dose.

The other major discussion and recommendation was for getting one of the other companies' vaccines as a booster (mix and match). People who received Pfizer-BioNTech may now receive Moderna or J&J, those who received Moderna may boost with Pfizer-BioNTech or J&J, and those who received J&J may receive either of the mRNA vaccines. The NIH conducted a study taking a look at a phenomenon called heterologous boost. It showed good effect! Moderna seemed to win the day with the best production of antibodies by the booster. Pfizer did well, too. J&J did create solid immunity, though not as good as the mRNA vaccines. Homologous boost (using the same company vaccine for the booster) created 4.2-to-76-fold increase in neutralizing activity while heterologous boost created 6.2-to-76-fold increase. Reactogenic effects (the arm pain, mild fever, and other temporary side effects) were similar in both groups (homologous and heterologous boost).

Now there are some limitations here. This was based on the measurement of antibodies (which, as we have discussed, is not always the best measurement of vaccine effectiveness because of the complexity of the antibodies our immune systems produce) at 2 and 4 weeks. The increases may settle out and be relatively even (Pfizer and Moderna probably have similar effects). The paper discusses preliminary/interim findings as measurements and data analysis are still ongoing. In addition, while they had over 400 participants, this was not a randomized, controlled trial made to represent the full US population.

So what does this all mean?

First of all,


There is a lot of talk about boosters, of course, but they are still only recommended for the groups I mentioned in my previous booster post (I'll list them below): those who are at higher risk for severe illness or at higher risk of exposure because of their living situation or occupation. If you are younger, have a competent immune system without one of those conditions, or you don't live in a larger group situation, the vaccines provide great protection!


If you're over 65, yes.

If you're 18-64 with one of the listed conditions that makes you high-risk for severe COVID infection, yes.

If you're 18+ and received J&J, yes.

If you're 18-65 in an occupation with high risk of exposure, weigh your risks and benefits and consider it. I did because I take care of COVID+ patients frequently and my potential for exposure is quite high.

More than boosters, the important thing is that as many people as possible get their first and/or second doses. The pandemic has persisted this long because not enough people are vaccinated. Former Secretary of State Colin Powell died this week. He was 84 years old and had received his vaccine, but also suffered from multiple myeloma, a cancer of the blood (put simply) that left him immunocompromised. I don't know if he had his booster. Conservative outlets and anti-vaxxer bloggers tried to spin it as "the vaccines aren't working!" but they conveniently left out what we know about those with compromised immune systems, and what we know about vaccines being a tool of public health, not solely individual protection. General Powell is dead because someone in his circle was not vaccinated or caught COVID from someone who was not vaccinated, and spread it to him - because the pandemic is still here and ongoing. If more people had been vaccinated, General Powell would likely still be alive today.

Scientists Dr. Nini Munoz (@niniandthebrain) and Dr. Liz Marnik (@sciencewhizliz) examined hospitalizations and deaths since the beginning of 2021, including breakthrough cases. There have been over 2 MILLION hospitalizations, with 370,000 deaths due to COVID-19 since January. About 31,000 of those hospitalizations and 7,200 deaths were in people who were vaccinated. That's such a small fraction involving breakthrough infections, among SO MANY deaths that could be prevented.

The vaccines are marvels of science. We have accomplished an incredible feat in creating a highly effective vaccine in record time without skipping any scientific steps. But vaccines remain a tool of PUBLIC health. They are not a personal choice - they are a choice for our families, our communities. For my patients, for my friends' children - please #GetVaccinated.

Eligibility for Boosters:

People >65 years old

People 18-64 with increased risk due to underlying medical conditions

  • Cancer

  • Stroke

  • Chronic kidney disease

  • COPD

  • Heart failure

  • Coronary artery disease

  • Cardiomyopathy

  • Obesity

  • Pregnancy/recent pregnancy (within 42 days)

  • Smoking (or former smoker)

  • Diabetes mellitus

People 18-64 with occupational or institutional exposure

  • Hospital/healthcare facility workers, caregivers, teachers, working in close proximity without ability to mask up or maintain distance

  • Residents of group homes, prisons, shelters, long-term care facilities

13 views0 comments

Recent Posts

See All

1st Presidential Debate 2024

I didn’t watch it live, but reviewing video -last night’s debate confirms a few things: One candidate is an old man who is a convicted fraud and rapist who lies loudly and constantly so he seems like


bottom of page