Effect of Pfizer COVID-19 Vaccine on Patients Taking Therapeutic Immunosuppressants

Those taking methotrexate had lower seroconversion rates compared to controls.

A recent study conducted by investigators from the St Johns Institute of Dermatology, in collaboration with the Centre for Rheumatic Diseases, has found that the functional humoral immunity from a single dose of the Pfizer COVID-19 vaccine is impaired by methotrexate but not by other targeted biologics.

Results from the study were published in the journal The Lancet Rheumatology and were presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID).

“The patients from this cohort were unique in that they were largely in remission and were treated with methotrexate or other targeted biological monotherapy without concurrent use of glucocorticoids,” Caoilfhionn M. Connolly and Julie .J Paik said in an attached commentary. “In addition to assessing serological conversion, Mahil and colleagues addressed the key components of the adaptive immune response to vaccination, including T-cell responses and neutralizing antibody responses.”

For the study, the team of investigators recruited patients who had a diagnosis of psoriasis that was confirmed by a dermatologist and were receiving methotrexate or targeted biological monotherapy.

The study included 84 patients with psoriasis and 17 healthy controls and all of the participants were eligible for the Pfizer COVID-19 vaccine.

Immunogenicity was evaluated immediately before and on day 28 (±2 days) after vaccination.

Findings from the study showed that seroconversion rates were lower in patients receiving immunosuppressants than in controls. Those receiving methotrexate had the lowest seroconversion rates, as well as significantly lower neutralizing activity against wild-type SARS-CoV-2.

Additional findings demonstrated that neutralizing activity was preserved in those receiving targeted biologics and that cellular immune responses were induced in all of the groups.

“Patients receiving immunosuppressive therapies should be prioritized for the regular schedule of vaccination (i.e., not a prolonged interval between doses) and should be aware of the potential for suboptimal vaccine responses, even after completion of the vaccine series,” Connolly and Paik said. “With the spectre of variants looming, vaccination will allow patients to achieve maximum protection and reduce the burden of COVID-19. In the interim, there is a need for ongoing vigilance in observing non-pharmacological preventive measures in these patients.”