Antibody Levels in Immunocompromised Patients after Second Dose of mRNA Vaccine

February 2, 2022

A Comment piece was recently published in The Lancet Rheumatology regarding the antibody responses in immunosuppressed patients with rheumatic and muscoskeletal diseases.

Researchers at Johns Hopkins tested antibody levels in patients at 1, 3, and 6 months after the second dose of an mRNA COVID-19 vaccine (Moderna and Pfizer). Patients with a previous infection of COVID-19 and those who received additional doses prior to antibody testing were excluded. Of 302 participants, inflammatory arthritis was the most common disorder (43%). Hydroxychloroquine and TNF inhibitors were the most frequently reported immunosuppressive medications (41% and 26%, respectively).

“Overall, 313 (96%) of 326 patients had positive antibody titers 6 months after two doses of the mRNA vaccines.” Antibody responses decreased from 1 to 6 months, but remained above the threshold for “predicted neutralizing capacity” in the majority of patients. Those who received the Moderna vaccine had a higher rate of positive antibody titers than those who received the Pfizer vaccine; this may be due to the fact that one dose of the Moderna vaccine is 100 micrograms versus 30 micrograms for Pfizer. Additionally, those on monotherapy produced more positive antibodies than those on combination therapy (94% versus 71%, respectively).

“All 13 patients (4%) with negative response at 6 months were on lymphodepleting therapy consisting of rituximab (ten patients), abatacept (two), or belimumab (one) in combination with another immunosuppressive therapy; nine (69%) were on concomitant glucocorticoid therapy.”

Memory B cells and cellular response were not recorded as part of this study.