LOS ANGELES - An unvaccinated health care worker set off a COVID-19 outbreak at a nursing home in Kentucky where the vast majority of residents had been already vaccinated, according to a new study from the U.S. Centers for Disease Control and Prevention.
According to the CDC study, the outbreak led to the infection of 26 facility residents — including 18 who had been vaccinated — and 20 health care personnel, including four who had been vaccinated. Two unvaccinated residents died.
The outbreak involved a variant of the coronavirus named R.1 that has multiple mutations in the spike protein, the CDC said.
While 90.4% of the nursing facility residents were vaccinated, and the majority of those who were infected by the outbreak did not develop major symptoms, 25% of vaccinated residents and 7.1% of vaccinated health care professionals were still infected. The CDC’s findings underline the concerns about risks to vaccinated people from mutated strains of the virus.
"In addition, four possible reinfections were identified, providing some evidence of limited or waning natural immunity to this variant," the study authors wrote.
The R.1 lineage variant has not been previously detected in Kentucky and is currently not on the CDC’s list of variants of concern.
"To protect SNF residents, it is imperative that HCP [health care personnel], as well as SNF [skilled nursing facilities] residents, be vaccinated. A continued emphasis on strategies for prevention of disease transmission, even among vaccinated populations, is also critical," the study authors wrote.
Separately, another CDC study found 22 possible COVID-19 infections among fully vaccinated individuals at nursing home facilities in Chicago: 627 coronavirus infections were detected among 78 nursing facilities in the February study. Two-thirds of the vaccinated individuals were asymptomatic. Two required hospitalization and one death occurred.
"The results in this report highlight the importance of COVID-19 vaccination in high-risk congregate settings such as SNFs," this study authors wrote.
Nursing homes, assisted living facilities and other kinds of elderly residences have been easing restrictions and opening their doors for the first time since the start of the pandemic.
Roughly 7.7 million doses have been administered at long-term care facilities, and over 2.8 million residents and staff have been fully vaccinated. 81% of Americans over the age of 65 have at least one dose of the COVID-19 vaccine, according to data by the CDC.