Taking care of a lot of immunosuppressed patients, one big question my Johns Hopkins colleagues and I have had throughout the pandemic has been: Will vaccines rescue them from the COVID-19 threat? Based on a new study , the answer appears to be: only for some.
The day that the FDA granted the Pfizer COVID-19 vaccine an emergency use authorization, we launched of vaccine immune responses in immunosuppressed solid organ transplant recipients. Among 436 COVID-naïve participants who received a first dose of mRNA vaccine, only 17% mounted detectable antibodies to SARS-CoV-2. This is in stark contrast to immunocompetent people who were vaccinated, of whom 100% mounted detectable antibody; that was true for people who had received either the or vaccine. We also found that those taking anti-metabolites, such as mycophenolate or azathioprine, were about five times less likely to develop antibody responses (8.75% detectable antibody in those taking anti-metabolites versus 41.4% in those not taking them).
Naturally, we were disappointed to see these findings, as we were hoping to be able to tell our immunosuppressed patients that the vaccines seemed to work well for them. Given this observation, the CDC should update their for vaccinated individuals to warn immunosuppressed people that they still may be susceptible to COVID-19 after vaccination. As the CDC guidelines are currently written, they assume that vaccination means immunity. Our study shows that this is unlikely for most transplant recipients, and one could guess that our findings (especially those concerning anti-metabolites) could also apply to other immunosuppressed patients, such as those with autoimmune conditions.
Of note, our has not found that immunosuppressed transplant patients are at increased risk of COVID-19 mortality as we thought might be the case. But regardless, the vaccine does not seem to work as well in this same population.
As a transplant surgeon, there are a few implications for my patients. First, it seems pretty clear that immunosuppressed individuals need (at least) their second vaccine dose; proposals to stop at one dose until the rest of the population is vaccinated apply to immunocompetent people, but not to my patients. Second, it is critically important for immunosuppressed individuals to realize that they are not necessarily immune after receiving the vaccine, and to talk to their providers about antibody testing before relaxing protective behaviors. Fortunately, semiquantitative antibody tests like the ones used in our study are widely available, and with neutralizing immunity.
Our study is ongoing, and soon we will have data from the second dose, as well as deeper studies of T-cell and B-cell responses, which can confer immunity even when . We are also studying . Enrollment is open, we welcome new participants, and we hope to share more information soon.
is a professor of surgery and epidemiology and associate vice chair of surgery at Johns Hopkins University School of Medicine and Bloomberg School of Public Health.