Immunocompromised Patients Exhibit Low Antibody Response Even After 2 Doses of mRNA Vaccine

June 3, 2021

This past March, results of a study monitoring the immune response to the COVID-19 vaccine in solid organ transplant patients indicated that antibodies were detected in only 17% of patients after the first dose of an mRNA vaccine. Since then, data from the same study has been published on the antibody response to the second dose of an mRNA vaccine in immunocompromised persons. Among 658 participants who received two doses of an mRNA vaccine, 15% had measurable antibody response after dose 1 and dose 2. Among 473 participants on antimetabolites, 8% exhibited an antibody response after dose 1 and dose 2. 

“Poor humoral response was persistently associated with use of antimetabolite immunosuppression.” Unfortunately, this may mean that immunocompromised individuals, even after taking a full dose of the vaccine, will not exhibit protective immunity to SARS-CoV-2. “Although no threshold has been established for protective immunity, antibody levels were well below that which has been observed in immunocompetent vaccines.” To read more about how people living with autoimmune disease and taking medications with antimetabolites may be affected by the vaccine, check out our Vaccine and Autoimmune Disease FAQ page and recommendations for those with specific autoimmune diseases.

“If someone had no, or limited, immune response to two doses, will a third dose help? Should the third dose be of the sample platform or a different platform? Is it reasonable for some patients to reduce immunosuppression, risking rejection, just to achieve an immune response? How do B cell and T cell responses look in immunosuppressed people?” These are some questions the National Vaccine Research Study for Transplant Recipients hopes to answer, which is ongoing and currently still open for enrollment.