Effects of SARS-CoV-2 vaccination on the severity of COVID-19 infection in patients on chronic dialysis

Background COVID-19 is associated with increased morbidity and mortality in patients with end-stage kidney disease on dialysis. Efficacy of SARS-CoV-2 vaccination to prevent severe COVID-19 disease in end-stage kidney disease patients remains limited. We compared the incidence of COVID-19-related hospitalization and death in dialysis patients based on SARS-CoV-2 vaccine status.Methods Retrospective study of adults on chronic dialysis within Mayo Clinic Dialysis System in the Midwest (USA) between April 1st, 2020 and October 31st, 2022, who had a laboratory test positive for SARS-CoV-2 by PCR. Incidence of both COVID-19-related hospitalization and death were compared between vaccinated and unvaccinated patients.Results SARS-CoV-2 infection was identified in 309 patients, including 183 vaccinated and 126 unvaccinated. The incidence of death (11.1% vs 3.8%, p = 0.02) and hospitalization (55.6% vs 23.5%, p < 0.001) was significantly higher in unvaccinated compared to vaccinated patients. Age at infection, sex, Charlson comorbidity index, dialysis modality, and hospital stays did not differ between the two groups. The incidence of hospitalization was significantly higher in partially vaccinated (63.6% vs 20.9%, p = 0.004) and unboosted (32% vs 16.4%, p = 0.04) patients compared to fully vaccinated and boosted, respectively. Among the 21 patients who died in the whole cohort, 47.6% (n = 10) died during the pre-vaccine period. The composite risk of death or hospitalization was lower among vaccinated patients after adjusting for age, sex and Charlson comorbidity index (OR 0.24, 95% CI 0.15-0.40).Conclusions This study supports the use of SARS-CoV-2 vaccination to improve COVID-19 outcomes in patients on chronic dialysis.