During the COVID-19 pandemic from June 30, 2021 to September 27, 2022, the Delta and Omicron variants of SARS-CoV-2 prevailed in the United States and likely contributed to higher infection and death rates among patients receiving maintenance dialysis compared with the general population, according to new data reported in Morbidity and Mortality Weekly Report.

The overall infection rate was 39.64 per 10,000 patient-weeks among unvaccinated patients on dialysis and 27.24 per 10,000 patient-weeks among patients who had completed a COVID-19 vaccination series, Jose Navarrete, MD, of the National Center for Emerging and Zoonotic Infectious Diseases at the Centers for Disease Control and Prevention in Atlanta, Georgia, and colleagues reported. The overall death rate was 1.74 per 10,000 patient-weeks for the dialysis population.

The SARS-CoV-2 infection rate in the dialysis population was 20.13 per 10,000 population-weeks during the Delta wave, 46.45 per 10,000 population-weeks during the first Omicron wave, and 25.05 per 10,000 population-weeks during the second Omicron wave. The corresponding SARS-CoV-2 infection rates in the general population were 20.73, 43.62, and 17.13 per 10,000 population-weeks, respectively.

COVID-19-related death rates in the dialysis population were higher than in the general population: 1.96, 2.66, and 0.59 vs 0.24, 0.26, and 0.06 per 10,000 population-weeks during the Delta and first and second Omicron waves, respectively.

Individuals older than age 65 years had the highest death rates in the general population. Noting that the dialysis population skews older, Dr Navarrete’s team found the highest death risk among patients on dialysis aged older than 75 years.

Patients receiving dialysis at a dialysis or long-term care facility have increased contact with patients and staff members, and some rely on shared transportation increasing their risks for infection, the investigators pointed out.

“These findings underscore the need for dialysis patients and staff members to stay up to date with primary COVID-19 vaccine and booster dose recommendations and for dialysis facilities to implement effective infection control strategies,” Dr Navarrete’s team wrote. These measures currently include early detection of symptomatic illness, appropriate sequestering of infected patients during dialysis sessions, barriers, correct use of personal protective equipment, and improved ventilation.

The highest infection and death rates occurred during the first Omicron wave. During the Omicron waves, the infection rate was lower among patients on dialysis who had received at least 1 monovalent booster dose than those who had not: 30.62 vs 33.69 per 10,000 patient-weeks.

“Approximately 70% of dialysis patients have completed a primary vaccination series, but only 54% received additional primary or booster doses, indicating substantial potential for improvement in vaccination coverage,” Dr Navarrete’s team reported.

During the second Omicron wave ending in September 2022, the investigators found no difference in the infection rate between those vaccinated and unvaccinated. They suggested this might be because of lower overall infection rates and declining vaccine effectiveness over time, as well as the emergence of new variants.

These analyses were based on weekly data from 7848 dialysis facilities including 518,798 patients reported to the CDC’s National Healthcare Safety Network.

Reference

Navarrete J, Barone G, Qureshi I, et al. SARS-CoV-2 infection and death rates among maintenance dialysis patients during Delta and early Omicron waves — United States, June 30, 2021–September 27, 2022 MMWR Morb Mortal Wkly Rep 2023;72:871-876. doi:10.15585/mmwr.mm7232a4