Objective: The effectiveness of COVID-19 vaccinations wanes due to immune evasion by the B.1.1.529 (Omicron) variant and diminished antibody titres over time. We aimed to evaluate the benefit of a fourth vaccination dose in patients with autoimmune rheumatic diseases (ARDs).
Methods: This retrospective analysis included ARD patients aged 18 years or older and members of Clalit Health Services in Israel (which at the time of the study insured 52% of the entire population), and covered the period from 16 January 2022 to 31 March 2022, when the predominant SARS-CoV-2 variant was Omicron. We compared patients without previous COVID-19 infection who had received three doses of the BNT162b2 vaccine (the control group) with those who had received the fourth dose. The primary outcome was COVID-19 infection, which was analysed using multivariate Cox regression in the entire cohort and within ARD subgroups. Secondary outcomes were COVID-19-related hospitalizations and COVID-19-related death.
Results: We included 43 748 ARD patients, of whom 27 766 and 15 982 were in the control and fourth vaccination groups, respectively. COVID-19 infection occurred in 6942 (25.0%) of the control group and 1754 (11.0%) of the fourth dose group (P < 0.001). Patients vaccinated with the fourth dose had a lower risk of COVID-19 infection than the entire cohort [Hazard Ratio (HR) 0.54, 95% CI 0.52, 0.58] and throughout every subgroup regardless of the baseline characteristic or medical treatment, except for rituximab. A similar association was observed for risk of COVID-19-related hospitalization (HR 0.36, 95% CI 0.22, 0.61) and of COVID-19-related death (HR 0.41, 95% CI 0.24, 0.71).
Conclusion: A fourth BNT162b2 vaccination of ARD patients was associated with favourable outcomes compared with three doses among patients with no history of COVID-19 infection.
Keywords: BNT162b2 vaccine; COVID-19; SARS CoV-2; autoimmune rheumatic diseases; fourth dose.
© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.