COVID-19 in Nursing Homes: Residents Up to Date on Vaccines Got Sick Less, Winter 2022–23

Nursing home residents up to date with COVID-19 vaccination, by region and by number of health care staff per facility, October 10, 2022–January 8, 2023. CDC.

Key points

• Nursing home residents who were not up to date with COVID-19 vaccines had 30%–50% higher weekly rates of new infection than residents who were.
• Being "up to date" in this period essentially meant having had the bivalent booster: in facilities that reported detail, more than 99% of up-to-date residents had received it.
• Yet by January 8, 2023, only 48.9% of residents were up to date — far below the 86.1% who had completed a primary series and 87.0% who had had a monovalent booster.

Why nursing homes

Older age, other illnesses and shared living put nursing home residents at high risk of infection and of severe COVID-19, including death. Earlier vaccines and boosters sharply cut illness and death among them. In fall 2022, recommendations added an updated bivalent booster protecting against the original virus and the Omicron BA.4 and BA.5 variants — but its benefit in nursing homes had not been measured.

The study

CDC's National Healthcare Safety Network (NHSN) used the weekly case and vaccination counts that CMS-certified nursing homes must report.

• 15,049 of 16,352 nursing homes (92%) in the 50 states and D.C. reported for at least one week of the 13-week period, October 10, 2022–January 8, 2023; about 14,791 reported each week.
• Up to date meant having a bivalent booster, or having finished a primary series or monovalent booster within the past 2 months (not yet eligible for the bivalent).
• Cases were matched to residents' vaccination status two weeks earlier, since a case's status is set by vaccination 14 days before the positive test.

Results

• In every week, rates were higher among residents who were not up to date; the incidence rate ratio ranged from 1.3 to 1.5, all statistically significant.
• The share of residents up to date rose slowly, from 37.5% to 48.9%, similarly across facility sizes and regions.

Selected weeks:

Why so few boosters?

Bivalent boosters were recommended only in fall 2022, leaving little time. Other possible reasons: a belief that more doses are unnecessary or don't work well, misinformation about how severe COVID-19 is, fatigue with changing guidance — and whether the vaccine is offered at the facility.

The findings match other studies showing bivalent boosters add protection against symptomatic infection, emergency and urgent care visits, and hospitalization in older adults, and produce a strong immune response in nursing home residents.

Limitations

• Nursing homes report data largely by hand, so misclassification is possible, especially as the definition of "up to date" changed.
• Crude rates do not account for time since vaccination, prior infection, age, other illnesses, community spread, staff vaccination or infection control.
• Residents boosted within the previous 14 days counted as not up to date, which would make the difference look smaller.
• "Not up to date" lumped together unvaccinated residents and those with some earlier doses.

Sources

Based on Heather Dubendris, Hannah E. Reses, Emily Wong et al., "Laboratory-Confirmed COVID-19 Case Incidence Rates Among Residents in Nursing Homes by Up-to-Date Vaccination Status — United States, October 10, 2022–January 8, 2023," Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; published by CDC. The report's table lists the same number of up-to-date residents for the weeks ending October 16, 2022, and January 8, 2023 (454,826), apparently a transcription error; the rates are shown as published.