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INTERVIEW BY STEPHANIE DESMON
For many immunocompromised patients, the regular two-dose COVID-19 vaccine regimen—and in some cases, even a third dose—didn’t provide sufficient immune protection. As a result, approximately 5 to 7 million immunocompromised people living in the U.S. have been struggling for over a year with how they will achieve vaccine-induced immunity.
In this Q&A, adapted from the January 14 episode of Public Health On Call, Dorry Segev, MD, PhD ’09, MHS ’09, professor of Surgery at the Johns Hopkins School of Medicine and professor of Epidemiology at the Bloomberg School, talks with Stephanie Desmon about his studies with immunocompromised patients and COVID-19 vaccination throughout the pandemic—and why he thinks an individualized approach is needed for this population.
WHERE ARE WE RIGHT NOW IN TERMS OF DOSE REGIMENS FOR IMMUNOCOMPROMISED PEOPLE?
When the vaccines came out, no one knew how immunocompromised people would respond to them. They were excluded from the big clinical randomized trials. Very early on, we started to measure antibody levels in people who are immunocompromised after one dose, after two doses—and it was very clear that the more immunocompromised you were, the lower your immune response to the vaccine. Two shots for many people who are immunocompromised was grossly inadequate. There was a good response to a third shot.
I care for transplant patients who take immunosuppression [drugs] to prevent their [transplanted] organs from rejecting, but that suppresses their immune system response to vaccines as well. In transplant patients, even with three shots in the currently recommended regimen, about half of transplant patients don’t reach a level of an antibody that correlates with clinical protection.
SO, THEY MIGHT AS WELL BE UNVACCINATED AS FAR AS HOW PROTECTED THEY ARE?
It’s likely that there’s some protection with regard to the severity of their disease. The fact that people with no antibody after two shots do sometimes demonstrate a lot of antibodies after three shows us that each dose primes the immune system. We’re measuring antibodies and neutralizing antibodies, but there are also memory B cells and T cells, which we don’t really have good ways of quantifying or correlating with protection.
I would say it’s absolutely critical for anyone who’s immunocompromised to get vaccinated. Even if they don’t have a lot of detectable antibodies, they likely have some amount of protection. They’re still at risk of acquiring the disease at a higher rate with more severe infection than people who are immunocompetent, although maybe not as severe as if they had not been vaccinated at all.
There are two dimensions to protection: One is, can we prevent you from getting COVID at all? The second is if you should get it, can we minimize disease severity?
Créditos: Comité científico Covid