The kinetics of humoral and cellular responses after the booster dose of COVID-19 vaccine in inflammatory arthritis patients

Introduction: Impaired immunogenicity of COVID-19 vaccinations in inflammatory arthritis (IA) patients results in diminished immunity. However, optimal booster vaccination regimens are still unknown, due to not unstudied kinetics of the immune response after booster vaccinations. Therefore, this study aimed to assess the kinetics of humoral and cellular responses in IA patients after the COVID-19 booster. Patients and Methods: In 29 IA patients and 16 healthy controls (HC) humoral responses (level of IgG antibodies) and cellular responses (IFN-{gamma} production) were assessed before (T0), after 4 weeks (T1), and after more than 6 months (T2) from the booster vaccination with BNT162b2. Results: IA patients, but not HC, showed lower anti-S-IgG concentration and IGRA fold change at T2 compared to T1 (p=0.026 and p=0.031). Furthermore, in IA patients the level of cellular response at T2 returned to the pre-booster level (T0). All immunomodulatory drugs, except IL-6 and IL-17 inhibitors for the humoral and IL-17 inhibitors for the cellular response, impaired the immunogenicity of the booster dose at T2. However, none of the immunomodulatory drugs affected the kinetics of both humoral and cellular responses (measured as the difference between response rates at T1 and T2). Conclusion: Our study showed impaired kinetics of both humoral and cellular responses after the booster dose of the COVID-19 vaccine in IA patients, which, in the case of cellular response, did not allow the vaccination effect to be maintained for more than 6 months. Repetitive vaccination with subsequent booster doses seems to be necessary for IA patients.