Clinical effects of third doses of mRNA COVID-19 vaccines among hemodialysis patients: a nationwide retrospective cohort study.
Cho AJin A, Jeong Seon A SA, Seo Yu Bin YB, Park Hayne Cho HC et al.
Evidence on the effectiveness of third-dose messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccination during the Omicron-dominant period in Asian hemodialysis (HD) patients remains limited. We evaluated the clinical effectiveness of a third mRNA vaccine dose against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hospitalization, and mortality in Korean HD patients. Using the Korea Disease Control and Prevention Agency-National Health Insurance Service database, we conducted a nationwide cohort study of HD patients aged ≥18 years who received two or three doses of BNT162b2 or mRNA-1273 before January 16, 2022. Study outcomes were SARS-CoV-2 infection, hospitalization, and death. Cox proportional hazards models were used to assess the associations between third-dose vaccination and clinical outcomes. Among 66,389 HD patients (mean age, 65.7 ± 12.9 years; 60.5% male), 55,125 (83.0%) received three vaccine doses and 11,264 (17.0%) received two doses. Receipt of three doses was associated with a significantly lower risk of SARS-CoV-2 infection (adjusted hazard ratio [aHR], 0.58; 95% confidence interval [CI], 0.56-0.60). Among 17,886 patients with SARS-CoV-2 infection, third-dose vaccine recipients had a lower risk of hospitalization (aHR, 0.65; 95% CI, 0.62-0.70) and 30-day mortality (aHR, 0.35; 95% CI, 0.30-0.41) compared with those who received two doses. Receipt of mRNA-1273 as the third dose was associated with lower observed risks of infection and hospitalization than receipt of BNT162b2. A third dose of an mRNA COVID-19 vaccine was associated with lower risks of SARS-CoV-2 infection, hospitalization, and mortality among HD patients during the Omicron-dominant period. These findings support the clinical importance of booster vaccination in this high-risk population.