
Vaccine effectiveness (VE) among nursing home residents up to date on their COVID-19 vaccines is 31.2%, according to new research in Morbidity and Mortality Weekly Report.
In today's study, up-to-date vaccination was defined as receipt of a bivalent (two-strain) COVID-19 mRNA vaccine dose or completion of a primary series within the preceding 2 months. COVID-19 infections with Omicron strains documented from November 20, 2022 and January 8, 2023, in the National Healthcare Safety Network (NHSN) were included in the analysis.
"The study period was chosen to coincide with both the inclusion of bivalent vaccine in the definition of up-to-date status and the increase in COVID-19 infections during the winter months," wrote the authors, from the Centers for Disease Control and Prevention (CDC) and elsewhere.
The study included 108,727 weekly reports from 14,464 nursing homes. Overall, 4,314,714 (48.1%) nursing home resident-weeks reflecting up-to-date vaccination status, and 52,853 (40.6%) of COVID-19 patients were up to date.
It is important that nursing home residents stay up to date with COVID-19 vaccines.
After adjusting for weekly incident case counts (stratified by up-to-date vaccination status) with weekly resident counts (stratified by up-to-date vaccination status) each week during the study period, up-to-date VE against infection was 31.2% (95% confidence interval, 29.1% to 33.2%).
"It is important that nursing home residents stay up to date with COVID-19 vaccines and, if eligible, receive an additional bivalent dose to optimize protection against infection and related complications,” the authors concluded.