COVID-19 infection and efficacy of vaccination in patients with rheumatic diseases during Omicron outbreak in South Korea: a prospective cohort study

Abstract

ObjectivesThis study aims to investigate COVID-19 epidemiological data in patients with autoimmune inflammatory rheumatic diseases (AIRDs) during Omicron wave and to identify clinical factors associated with infection, including COVID-19 vaccination.MethodsThis prospective longitudinal study was performed between January and October 2022 in South Korea. Patients were classified into AIRD and non-AIRD groups according to their underlying diseases. COVID-19 status, date of confirmed infection and vaccination status were captured from the patient survey and national database. The COVID-19 incidence during the study period was examined and compared between the two groups. The effect of clinical factors on the infection rate was analysed in the AIRD group.ResultsA total of 1814 patients (1535 and 279 in the AIRD and non-AIRD groups, respectively) were analysed. During the study period, 857 COVID-19 cases were reported in 834 patients (46.0%). The infection rates in the AIRD and non-AIRD groups were comparable. In the AIRD group, older age (≥70 years) and glucocorticoid use were significantly associated with a lower rate of COVID-19 infection. The third booster vaccination significantly lowered the incidence of COVID-19 (adjusted HR 0.85 (95% CI 0.73 to 0.99)), and the prophylactic effect was more evident in patients aged <70 years (0.81 (95% CI 0.69 to 0.95), p value for interaction 0.036).ConclusionThe risk of SARS-CoV-2 infection with the Omicron variant did not increase in patients with AIRDs. The third booster vaccination regimen decreased the infection rate in patients aged <70 years.