As we enter our second pandemic Thanksgiving holiday, I'm reminded we have a lot to be thankful for compared to a year ago. This time last year the only people who were vaccinated against COVID-19 were the relatively small numbers of subjects randomized to receive vaccine in the clinical trials. Now we know that our approved and authorized vaccines are both safe and effective and clearly have put a dent in the pandemic in the US. Also, we now have treatment options including two oral medications making their way through the FDA evaluation process. Unlike last year, many families will be able to gather safely to celebrate the holiday. For those that do, please be safe both in your travel plans and in your infection control practices.
The Number Needed to Vaccinate
Last week the FDA authorized booster doses of mRNA vaccines, and subsequently the CDC/ACIP met on November 19 to make their recommendations. Now everyone 18 years of age and older can get a booster if desired.
I won't bother to recite all of the data presented, suffice to say the new experimental data submitted by Pfizer and Moderna consisted primarily of antibody titers one month after a booster dose, along with some limited safety information. I did want to mention the number needed to vaccinate (NNV) just to give you an idea of how many people benefit from boosters at different age groups. NNV is a spinoff of the term number needed to treat which is another way of looking at data beyond p values. It was hoped it would be useful in explaining risks and benefits to lay people, but that hasn't quite been realized.
Dr. Oliver's presentation at ACIP looked at NNV for different age groups, telling us how many people would need to be vaccinated to prevent one additional person being infected or hospitalized with COVID-19. Slides 37 and 38 in her presentation display the data in graphical form.
Speaking just about the Pfizer data (NNVs are higher - i.e. less beneficial - for Moderna due to longer persistence of antibody), for persons like me 65 years and older 481 would need to receive a booster dose to prevent 1 additional hospitalization over a 6 month period. That's not bad, but of course the numbers get higher in the younger age groups. For 50-64 NNV is 2051, then 3361 for 30-49 year-olds and finally 8738 for the 18-29 year age group, which is not a great benefit. Know that these are predictions based on modeling and a lot of assumptions, but I think they are useful numbers to help you understand the magnitude of booster benefit. If you are like me, you're getting a lot of questions from parents about booster doses for teenagers and younger. Don't worry too much about that now, boosters aren't likely to be a big help for them. We'll know more once the children in the clinical trials have 6-month antibody levels drawn, coming soon.
Addressing Vaccine Hesitancy
Boosters aren't the way out of this mess, we still need to vaccinate the unvaccinated. According to multiple polls, a core group of adults in the US aren't going to be convinced to choose vaccination no matter what data are explained. They have made a decision and only choose to look at information that supports that decision. However, a lot of unvaccinated folks are open to discussion. For them, a new toolkit from our surgeon general, Dr. Vivek Murthy, is a good approach to try to correct misinformation. His advice to healthcare providers has 5 points: Listen, Empathize, Point to credible sources, Don't publicly shame, and Use inclusive language. It's a 22-page easy read, please take the time to look it over and decide how you can use it in your practice.