COVID-19 vaccine less effective for some immunosuppressed patients, study finds


The novel coronavirus (COVID-19) vaccines may be less effective for some immunosuppressed patients, according to new findings published in a research letter in JAMA.

Among 436 participants, organ transplant recipients with no prior COVID-19 diagnosis who received a first dose of mRNA vaccine, only 17 percent mounted detectable antibodies to SARS-CoV-2. This is in stark contrast to immunocompetent people who were vaccinated, of whom 100 percent mounted detectable antibody, which was true for people who had received either the Pfizer-BioNTech or Moderna vaccine, the authors said.

The researchers also said they found that those taking anti-metabolites, such as mycophenolate or azathioprine, were about five times less likely to develop antibody responses—8.75 percent detectable antibody in those taking anti-metabolites versus 41.4 percent in those not taking them.

While the study focused on transplant recipients, the authors said transplant recipients, and the findings, especially those concerning anti-metabolites, could apply to other immunosuppressed patients, such as those with autoimmune conditions. While previous research has not found that immunosuppressed transplant patients are at increased risk of COVID-19 mortality, the vaccine does not seem to work as well in this same population, the authors said.

These findings of poor anti-spike antibody responses in organ transplant recipients after the first dose of mRNA vaccines suggest that such patients may remain at higher early risk for COVID-19 despite vaccination. Deeper immunophenotyping of transplant recipients after vaccination, including characterization of memory B-cell and T-cell responses, will be important in determining vaccination strategies as well as immunologic responses after the second dose, the researchers said.

The research is ongoing and continues to enroll new participants.

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