Impact of COVID-19 vaccination on infection risk and clinical outcomes in patients with end-stage kidney disease undergoing dialysis: A nationwide retrospective study in South Korea

Background and hypothesis Patients with end-stage kidney disease (ESKD) on dialysis face an increased risk of morbidity and mortality following SARS-CoV-2 infection, with concerns that their antibody response to COVID-19 vaccination may be lower than that of the general population. However, the effectiveness of the COVID-19 vaccination in ESKD patients remains unclear. This nationwide retrospective cohort study examined the association between COVID-19 vaccination and the risk of SARS-CoV-2 infection in ESKD patients on dialysis. Methods A total of 14,498 vaccinated patients and 14,498 unvaccinated controls, matched by the propensity score, were followed from February 26, 2021, to December 31, 2021, using data from the Korean National Health Insurance Service linked to the Korea Disease Control and Prevention Agency data. Cox proportional hazard regression models were used to assess the association between vaccination status and risk of SARS-CoV-2 infection and serious outcomes. Results In the study population (mean age 63.2 years, SD 14.5; 53.7% male), SARS-CoV-2 infection occurred in 375 (1.3%) individuals. In the vaccinated cohort, there were 127 (0.9%) SARS-CoV-2 infections and 37 (0.3%) serious COVID-19, compared to 248 (1.7%) SARS-CoV-2 infections and 107 (0.7%) serious COVID-19 in the unvaccinated cohort. COVID-19 vaccination was associated with a lower risk of SARS-CoV-2 infection (HR, 0.47; 95% CI, 0.38–0.58; P < 0.001) and serious COVID-19 (HR, 0.32; 95% CI, 0.20–0.49; P < 0.001). Conclusions In this nationwide study of Korean dialysis patients, COVID-19 vaccination was associated with a significantly lower risk of SARS-CoV-2 infection and adverse outcomes in patients with ESKD.