COVID-19 Vaccine Booster Update(finally)

It has taken way too long, but I finally feel I can write an update about vaccine boosters without the information changing 3 times before you see it in your inboxes. While this update is intended to provide info about adult boosters, here is first a brief note about the kids:

Pediatric COVID-19 Vaccines – Widely anticipated, it appears that pediatric (age 5yo-11yo) vaccines will be approved this week. The first step in this process happened last Tuesday; a special subcommittee of the FDA voted that the vaccine is safe, effective and needed for the 5yo to 11yo age group. The FDA then approved the Pfizer vaccine for children on Friday. The final two steps are approval by the CDC advisory panel (meeting on Tuesday, Nov 2) and the release of the CDC recommendations, which should happen after the advisory panel vote. I will send out a more detailed update on pediatric vaccines later this week, but I wanted to provide this timeline for you.

Now for the adults – On October 21st, the CDC advisory committee met and created its recommendations for COVID-19 vaccine boosters:

1. If you received a vaccine from J&J, you should receive a booster shot at least 2 months after your initial dose.

2. If you received either a Pfizer or Moderna vaccine, you should/may* receive a booster dose 6 months after your initial dose if:

· You are 65 years old and older

· You are 18+ years old with underlying medical conditions**

· You are 18+ years old and work or live in a high-risk setting

3. If you are moderately to severely immunocompromised***, you should get a third mRNA vaccine booster 4 weeks after your second dose of Moderna or Pfizer. You should get a fourth dose 6 months after your third dose.

Which Booster Should You Get? This has been the million-dollar question, and while we do have more clarification, there are still some unknowns. The CDC has determined that you can choose to booster with any of the COVID-19 vaccines that are authorized in the United States. This was based on a study of 458 people that was released 2 weeks ago. Mixing and matching different vaccines is not new; this strategy has been used with other diseases such as Ebola. Not only is the “mix and match” method safe, in many cases it may provide a greater immune response than getting a booster of whichever vaccine you received initially. It will also make it easier for people to get boosters in areas where there may be a shortage of some vaccines. As with most everything else COVID-19 related, you should weigh risks and benefits when making your decision about which vaccine booster to get. One big unknown…the study was done with a full-dose booster of Moderna; however, the recommended Moderna booster is now a half-dose. We don’t yet know how much that will affect the immune response when combined with other vaccines.

Benefits (looking at the immune response to different mix-and-match options):

· For the J&J vaccine the data is clear that the most benefit comes from a mRNA booster. A Moderna booster gives the greatest immune response, but the Pfizer booster also works well. Interestingly, getting the J&J and then Moderna shot was more effective than the Moderna shot and then a J&J.

· If you initially received the Moderna vaccine, you could get a booster with either a Moderna shot or a Pfizer shot; there was equal benefit.

· If you initially received the Pfizer series, the Moderna booster seems to be best; however, the Pfizer booster is effective as well.

Risks:

Myocarditis (inflammation of heart)

· Approximately 2500 cases out of 366 million doses of mRNA vaccine administered.

· No deaths have been linked to vaccine-induced myocarditis, and all cases have fully recovered in ~6 months.

· Males under 30yo seem to be at greatest risk, after their second dose of an mRNA vaccine.

· Risk appears to be slightly higher with Moderna than Pfizer.

· We would expect the risk to be less with the booster as it has been longer since the last dose.

· My take home message – if you are a male under 30 and not at especially high risk, consider waiting until we have more data, or choose a Pfizer booster vs a Moderna (or choose a J&J vaccine).

Blood clots

· Blood clots have been seen after administration of the J&J vaccine – but still only 47 cases out of 15.3 million shots administered in the US.

· The risk appears to be greatest in females aged 30-49 yo.

· My take home message – females under 50 (and definitely in the 30-49 yo range) should consider getting an mRNA booster, rather than the J&J booster.

The over-riding message, however, is this – The vaccines are safe, and are protective against severe disease and death. This is supported by the fact that of the over 1,000 people currently hospitalized in Colorado with COVID-19, almost 80% are unvaccinated. If you are not yet vaccinated, please reconsider. If you are over 65 or otherwise meet the criteria for a booster, please get that booster when you are eligible.

As always, stay safe!

Dr. Husney

*Those 15-64 years with underlying medical conditions SHOULD get a booster as the risk of severe illness from COVID-19 increases with age. Those 18-64 yo with underlying medical conditions MAY get a booster, based on individual risks and benefits.

**Underlying medical conditions include: Chronic lung diseases, Type I and II diabetes, cancer, weakened immune system, organ transplant, chronic kidney or liver disease, dementia, heart conditions or stroke, overweight and obesity (BMI>25), pregnancy, mental health conditions, smoking (current or former), substance use disorders. The link for the full list is: https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/people-with-medical-conditions.html

*** https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/immuno.html