Some Immunosuppressants Dampen Vaccine’s Ability to Create Immune Response

March 24, 2021

Last week, researchers at Johns Hopkins released the results of a cohort study measuring the antibody production of 436 solid organ transplant recipients following their first dose of an mRNA vaccine. Immunocompromised patients were excluded from mRNA clinical trials. The results of this study – although they’re exclusive to solid organ transplant recipients – can shed light on antibody production for those on immunosuppressant therapies. 

Participants collected blood samples at home with a TAII blood collection device or standard venipuncture in a medical office, which was then tested for antibodies against the SARS-CoV-2 spike protein. Tests were conducted 14-21 days after receiving the first dose of the Moderna or Pfizer vaccine. 

The median time since transplant was 6.2 years, and participants reported taking tacrolimus, corticosteroids, mycophenolate, azathioprine, sirolimus and everolimus as part of their maintenance regimen. Mycophenolate and Azathioprine have antimetabolite agents and can be used to treat autoimmune diseases such as lupus, rheumatoid arthritis, and IBD (Crohn’s Disease and Ulcerative Colitis) (1, 2). 

Antibodies were detectable in 75 of 436 participants following the first dose of the vaccine. This is approximately 17% of participants. Transplant recipients on antimetabolite therapies like Mycophenolate and Azathioprine were around 5x less likely to develop an antibody response than those not receiving such immunosuppression therapy. 

Overall, younger participants who were not under antimetabolite maintenance immunosuppression and received the Moderna vaccine were more likely to develop antibodies. Those who received the Moderna vaccine were more likely to develop antibodies than those who received the Pfizer vaccine (60% versus 31%). While clinical trials observed a 100% antibody response for both the Moderna and Pfizer vaccines, this vast discrepancy shows the impact of immunosuppressants on the vaccine’s ability to create a robust immune response. 

Vaccine recipients taking immunosuppressants should be made aware that they may still be high-risk to COVID-19. Dr. Segev, associate vice chair of surgery at Johns Hopkins University School of Medicine and Bloomberg School of Public Health, as well as a co-author of the study, is calling for the CDC to update their guidelines to reflect the ongoing risk immunosuppressed people, as well as certain autoimmune patients, may have to COVID-19 even after vaccination (3). This study is ongoing and researchers are in the process of collecting data on antibody production after receiving a second dose of the vaccine, as well as T-cell and B-cell responses when antibodies are scarce.

3-D rendering of B cell antibodies attacking COVID-19 cellGraphic rendition of yellow B cells (antibodies) attacking a COVID-19 cell