Vaccination coverage according to immunosuppression level among adults with non-rheumatoid arthritis rheumatic diseases: a retrospective observational study in Korea.

Patients with autoimmune inflammatory rheumatic diseases are particularly vulnerable to infectious diseases. Accordingly, a broader range of vaccines and, in some cases, additional doses are recommended for these patients compared with the general population. This study investigated the vaccination status of adult patients with non-rheumatoid arthritis rheumatic diseases (NRRDs). This retrospective study was conducted in the rheumatology outpatient department of a tertiary care hospital and included adult patients (aged ≥19 years) with NRRDs who received glucocorticoids and/or disease-modifying antirheumatic drugs from January 2023 to March 2023. Among these patients, we compared vaccination rates between high-level immunosuppression (HLI) and non-HLI groups. HLI was defined as current biologic use or prednisolone equivalent at a dose of ≥20 mg/day for ≥14 days. Of the 4,070 patients with NRRDs, 1,522 (37.4%) were in the HLI group. Overall vaccination rates (complete plus partial vaccination) were significantly lower in the HLI group than in the non-HLI group for influenza (20.2 vs. 31.0%, p<0.001), hepatitis B (59.5 vs. 68.8%, p<0.001), pneumococcal disease (12.9 vs. 26.9%, p<0.001), and herpes zoster (4.3 vs. 10.8%, p<0.001). Overall, vaccination rates were low among patients with NRRDs, with especially low rates in the HLI group. These findings highlight the need for systematic vaccination strategies.