If you are confused over whether or not you should get another bivalent COVID vaccine booster, you are not alone. While the FDA has suggested that it is considering recommending a second booster for older folks and the immunocompromised, advice from the vaccine experts has been all over the place. Let me give a little historical background for the current lack of consensus.
Your immune system has two main components: B cells (born in the Bone marrow) and T cells (born in the Thymus). B cells make antibodies, the lobster-like proteins (yes, two claws and a tail) that grab onto surface components of the COVID virus. T cells attack virus-infected cells by recognizing fragments of degraded virus expressed on the infected cell surface. Immunologists who study B cells think that they are the more important; those who study T cells are convinced that they are the more important immune response. Let’s just call them the B-team and the T-team for the moment (are scientists competitive; you betcha).
From the B-team perspective, it is clear that antibody responses to the current COVID vaccines start to wane after 6 months, particularly in the elderly. Another vaccine booster would stimulate more antibodies, so the B-team supports this recommendation.
The T-team has a different outlook. Once T cells have been activated by vaccine or infection, they tend to last a long time. In the case of COVID vaccines, the early data suggests that memory T cells are not yet declining. For other virus infections, T cell responses can last a lifetime. For these reasons, the T-team is not so sure that another COVID vaccine booster is necessary.
The vaccine advisory groups are a mix of B- and T-team members. They have had difficulty reaching a consensus recommendation because of their different views on which immune response is the more important. In addition, a second strange argument has been put forward that a second bivalent booster should not be recommended because only 40% of the U.S. population has got the first shot. Public outreach should focus on getting everyone to gain some protection against the current COVID strains rather than protecting the most vulnerable, they say.
Forget the B-team and T-team differences. Another booster shot will provide more protection than doing nothing. Daily COVID deaths have declined to 255 (as of late March), but that is not an acceptable outcome. If you are over 65 or have any condition that reduces your immune response, the wise choice is to get a second bivalent COVID vaccine booster if it has been six months or more since your first shot.