Protecting nursing home residents from severe COVID-19 remains an important part of infection prevention, particularly as new variants continue to emerge.

A new study published in the Journal of the American Medical Directors Association (JAMDA) evaluated how well the updated monovalent KP.2 COVID-19 vaccine protected nursing home residents against infection, hospitalization, and death—and how long that protection lasted.

Researchers followed residents living in Veterans Affairs nursing homes during the 2024 respiratory virus season, comparing those who received the updated KP.2 vaccine with similar residents who did not.

The results showed the vaccine continued to provide meaningful protection against severe illness for months after vaccination.

At 12 weeks, vaccine effectiveness against COVID-19-associated hospitalization or death was 77%. By 18 weeks, protection had declined but remained at 53%. Protection against COVID-19 infection itself declined more rapidly, decreasing from 38% at 12 weeks to 4% by 18 weeks.

The findings reinforce an important distinction seen with many respiratory vaccines. While protection against infection may diminish over time, protection against the most serious outcomes—including hospitalization and death—can remain substantially stronger.

Based on their findings, the authors suggest that a twice-yearly COVID-19 vaccination strategy may help maintain protection for nursing home residents, a population that continues to face increased risk of severe disease.

As recommendations continue to evolve, studies like this provide valuable evidence to help providers evaluate vaccination strategies and protect vulnerable residents throughout the year.