A new study published this week found that the second COVID-19 booster that was made available to U.S. adults older than 50 this year was highly effective at protecting nursing home residents from hospitalizations and deaths, though its ability to prevent infections was not as potent.
The analysis, published in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report, compared nursing home residents who received a second original mRNA booster dose to those who did not get the additional shot.
According to the study, the second shot was 90 percent effective at preventing coronavirus-related deaths and 74 percent effective at preventing severe cases that led to either hospitalizations or deaths.
The shot was about 26 percent effective at preventing infection, however. This study looked at cases between March 29 and July 25. It was within this period that the BA.5 omicron subvariant grew to become dominant in the U.S.
By the end of July, BA.5 was accounting for four out of five coronavirus cases, and experts had noted its ability to evade protection from immunization and prior infection.
The 9,527 nursing home residents who were included in the study had received their booster within 60 days when they were followed up on by researchers. In order to be eligible, participants had to have stayed in a nursing home for more than 100 days, spent less than 10 outside of the facility and received three prior vaccine doses, with the last dose received more than 120 days beforehand.
Nearly 200 nursing homes from 19 states were included in the study.
Nursing homes have been disproportionately impacted by the coronavirus throughout the pandemic. Roughly three out of four COVID-19 deaths have been among those over the age of 65. When the delta variant spread throughout the U.S. last year, coronavirus deaths rose at a faster rate in nursing homes than in the rest of the country.
“These findings suggest that among nursing home residents, second mRNA COVID-19 vaccine booster doses provided additional protection over first booster doses against severe COVID-19 outcomes during a time of emerging Omicron variants,” researchers wrote.
“Facilities should continue to ensure that nursing home residents remain up to date with COVID-19 vaccination, including bivalent vaccine booster doses, to prevent severe COVID-19 outcomes.”
White House COVID-19 response coordinator Ashish Jha hailed the study’s findings.
“This is why we’re so focused on ensuring folks, particularly the high risk, get the latest vaccine,” Jha tweeted.
If they have not been recently vaccinated once more or infected with the virus, many of the participants in this study would now be eligible to receive the bivalent omicron-specific COVID-19 booster. The updated shot was authorized at the end of August.
The White House has strongly encouraged eligible individuals to get the bivalent booster, hoping to avoid another surge in coronavirus cases in the fall and winter. The dose has been followed by some uncertainty, as it was approved before a full human study was completed, with both Pfizer and Moderna submitting animal data, as is done for annual flu shots.
Pfizer and Moderna have recently submitted applications seeking authorization from the Food and Drug Administration to administer their shots in younger populations. Pfizer’s bivalent booster is authorized for children as young as 12, while Moderna’s is currently only authorized for adults.