Boost Now or Wait for the New Booster?
I have been asked many times in the last few weeks, especially now that we are having signs of a new surge (as a reminder – when I use the word surge, I mean a significant and sustained increase in COVID-19 cases; I am not using it as an indicator of magnitude, i.e., that the number of cases, or hospitalizations, or whatever indicator one might wish to use, has or will hit some arbitrary threshold) – whether one should get a bivalent booster now (if they never received a bivalent booster or if they qualify for two and got the first, but not the second) or wait for the new monovalent boosters that are planned for this fall.
The FDA has indicated that they advised vaccine manufacturing companies of their intention to move to an annual COVID-19 vaccine update. In June of this year, the FDA provided guidance to these companies that the fall booster should be a monovalent vaccine (meaning the spike protein from on variant, as opposed to last year’s booster, which was a bivalent vaccine comprised of two spike proteins – one from the original form of the virus and the other from the BA.4/BA.5 variant) derived from the XBB.1.5 variant.
At that time, vaccine companies indicated that new vaccines could be ready in August, and perhaps even in late July. While the FDA has to approve the new vaccines, the CDC issues the specific guidance as to who is eligible for the booster, timing of vaccines and whether it is safe and effective to administer the COVID vaccines together with other vaccines.
We have a new CDC director who I have been very hopeful would be committed to more timely and more clear communication than what we got with the previous director. So far, I am disappointed. She has stated that the vaccines will likely be available to the public in October, though more recently, she has indicated that it might be as early as late September. Regardless, she has not (to my knowledge) explained to the public why the delay. Pfizer has indicated that they already have the vaccines prepared and have already submitted their paperwork for FDA approval. Novavax (currently approved only for those ages 12 years and older that is a more traditional type of vaccine as opposed to the mRNA vaccines produced by Pfizer and Moderna), has indicated that it will be filing for approval of its updated vaccine this month. So far, no explanation as to why it would take another 6 – 8 weeks to get these vaccines out to the public.
Until the CDC’s vaccine committee meets and recommends guidance and the CDC director signs off on those recommendations, the vaccines will not be made available to the public and we won’t know the answers as to who can get the vaccines, the timing of vaccines relative to prior vaccination or infection, and whether these COVID vaccines maintain their safety and effectiveness if administered with other vaccines, such as the newly approved RSV vaccines for persons over age 60 and the influenza vaccine that will be offered this fall.
So, now back to the question. Should a person who has not received the bivalent booster get boosted now, or alternatively, a high-risk patient who received one bivalent booster shot, but not the second, get a bivalent booster now or wait for the new monovalent vaccines anticipated to be available in October?
Although it is frustrating that we don’t yet have guidance from the CDC about timing for the new monovalent booster, my guess is that they are going to advise that the new booster not be administered within 4 months of a prior COVID bivalent booster shot (and I anticipate they will state 2 months for immunocompromised persons). This recommendation would be based on recent data as to the optimal spacing of boosters to generate the maximal immunological response and would be consistent with the guidelines issued last year for the bivalent vaccine booster administration. That data is not crystal clear, but seems to suggest that you want at least 2 months between boosters and that 4 months is better than 2, with some remaining question as to whether 6 months might be even slightly better than 4.
Now to answer the question. This would be how I would analyze and answer this question from a patient or their physician:
Is the patient significantly immunocompromised? If yes, go to Question 1; if no, go to Question 2.
- If you are significantly immunocompromised and it has been 2 or more months since your last booster, ask your physician about getting another bivalent vaccine now. It will be nearly two months until the new boosters are available, and I would doubt that ACIP will recommend and the CDC director would adopt a requirement for you to wait four months from your last vaccination to get the new vaccine.
- When was your last COVID vaccine dose? If < 3 months, wait for new vaccine. If > 4 months, go to Question 3.
(If the answer is > 3 months ago, but < 12 months, we can be fairly confident that the person has little protection against getting infected, but likely strong protection against severe disease or death, unless they have an immune deficiency or significant immunocompromising condition.)
3. Can you limit your exposures until you can be vaccinated in October (work remotely, avoid large groups of people, wear well-fitting N95 masks when around others outside your family, household family members similarly able to limit exposures, etc.)? If so, wait for new booster. If not, go to question 4.
Is the patient at high risk for severe disease – age > 65 years and/or significant underlying health conditions that would place the patient at increased risk? If no, go to Question 4; if yes, go to Question 5.
4. Do you have to or plan to engage in situations that will create high risk of exposures between now and October (for example, international travel, health care worker, school teacher in a school that is not taking precautions, daycare worker, etc.) and you did not receive the bivalent booster within the past 12 months? Consider getting bivalent vaccine booster now and then getting new monovalent vaccine as soon as you qualify (my guess is it would be 4 months after your bivalent booster dose, but in any event, wait at least 2 months before getting the new booster). If the patient has had 1 dose of the bivalent booster, wait for new monovalent booster, but add mitigation measures.
5. Do you have to or plan to engage in situations that will create high risk of exposures between now and October (for example, international travel, health care worker, school teacher in a school that is not taking precautions, daycare worker, etc.), but you have received one dose of the bivalent booster within the past 12 months? If the bivalent vaccine dose was received in the past 3 months, wait for the new monovalent vaccine booster, but add mitigation measures and consider postponing your international travel until at least several weeks after being boosted with the new booster shot. If your dose of bivalent vaccine was received more than 4 months ago, and especially if it was 6 or more months ago, consider getting a second bivalent vaccine booster shot now and then getting the new monovalent vaccine as soon as you qualify (my guess is it would be 4 months after your bivalent booster dose, but in any event, wait at least 2 months before getting another booster).
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