Effect of time interval and immunosuppressive treatment on durability of humoral immune response in rheumatoid arthritis patients following COVID-19 vaccination

Background and objective: The durability of humoral immune response for medium term period of COVID-19 vaccines in Rheumatoid arthritis patients and the role of immunosuppressive treatment have not been yet well investigated. Therefore, we aimed to evaluate the influence of time and immunosuppressive medications on the vaccine efficiency in rheumatoid arthritis patients compare to controls. Methods: This case control study was conducted from November 2021 to January 2023 included one hundred thirty-one subjects, divided into four groups; where the first group consist of (n=49) unvaccinated rheumatoid arthritis patients, while the second group consist of (n=34), vaccinated rheumatoid arthritis patients, compared with other two group of healthy subjects (n=25 unvaccinated and 23 vaccinated). Blood samples were collected (12 to 16) weeks after the second vaccine dose receipt for measuring serum IgG. Results: The difference in mean of IgG between the four study groups was non-significant (P = 0.079), the vaccinated rheumatic patients mean IgG 1.43 and 1.65 in vaccinated healthy control. The mean IgG among vaccinated RA patients on biological treatment was 1.70, and higher than non-biological treatment group (1.03). The prevalence of IgG positivity was significantly (P = 0.005) higher among the controls (56.3%) than the Rheumatoid arthritis patients (31.3%), and significantly higher among the vaccinated (50.9%) than the unvaccinated (32.4%) with (P = 0.033). The same pattern observed when the four groups are compared (P = 0.007). Conclusion: IgG positivity rate obviously decreased mainly in Rheumatoid arthritis groups after medium time interval, with no significant effect for immunosuppressant drugs on vaccination response. Keywords: Humoral immune response; COVID-19 vaccine; Durability; Immunogenicity; Rheumatic disease.