COVID-19 Among Dialysis Patients in the Delta and Early Omicron Waves, 2021–2022

People on maintenance dialysis are at higher risk of SARS-CoV-2 infection and its severe outcomes, including death — but how often they were infected or died, and how much vaccination helped, wasn't well described. Since November 2020, CDC's National Healthcare Safety Network (NHSN) has collected weekly data on infections and deaths from dialysis facilities; during the COVID-19 public health emergency, the Centers for Medicare & Medicaid Services required facilities to report.

The data

7,848 dialysis facilities reported on 518,798 patients from June 30, 2021, to September 27, 2022, divided into three waves:

An infection was any positive test in the previous 7 days; a COVID-19-related death was the death of a patient not yet fully recovered from infection.

What they found

Infections among dialysis patients by primary-series and booster vaccination status, June 2021–September 2022. CDC

• Both infection and death rates peaked in the first Omicron wave.
• In the Delta and first Omicron waves, vaccinated patients had lower infection rates than unvaccinated ones, and in the first Omicron wave, boosted patients had lower rates than those without a booster.
• In the second Omicron wave, there was no difference — perhaps because of lower overall infection rates, waning vaccine effectiveness and new variants.

Compared with everyone else

In the U.S. population, infection rates were 20.73 per 10,000 population-weeks in the Delta wave, 43.62 in the first Omicron wave and 17.13 in the second; death rates were 0.24, 0.26 and 0.06. Dialysis patients' rates followed the same pattern over time.

Infection and death rates in the U.S. population by age, and among dialysis patients. CDC

But dialysis patients tend to be older, and their infection rate was higher than that of the U.S. population over 65 — while their death rate was higher even than that of the U.S. group with the highest death rates, people over 75. Compared with the general population, dialysis patients likely had higher rates of both infection and death.

Why dialysis patients are vulnerable, and what helps

Most must travel to a dialysis facility three times a week for treatment alongside other patients and staff; many use shared transport, and about 7% live in long-term care facilities.

• Vaccination: a two-dose mRNA series appears protective despite a slightly weaker immune response, and side effects are no different than in others. About 70% of dialysis patients had completed a primary series, but only 54% had additional or booster doses — so education, countering misinformation and on-site vaccination remain important.
• Infection control: early detection of symptoms, placing infected patients appropriately, correct use of personal protective equipment, and safe protocols for ending precautions; plus barriers between patients and better ventilation and indoor air.

Limits

The data cover outpatient facilities (over 90% of U.S. maintenance dialysis patients), so home and peritoneal dialysis patients may be under-represented; facilities self-report; the death definition may count some deaths not caused by COVID-19; aggregate data didn't allow death rates by vaccination status or adjustment for age and illness; and dialysis patients may simply have been tested more.

Sources

Based on 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 volume 72, number 32, Centers for Disease Control and Prevention; a work of the United States government in the public domain. The report gives booster and non-booster infection rates for "the first and second Omicron waves" alongside the dates of the first wave only, so those two figures aren't given here.