COVID-19 boosters add about 70 percent extra protection against omicron, which lasts four to five months, a study published Sept. 23 in the Journal of the American Medical Association found.
Renton, Wash.-based Providence researchers conducted the study at sites across six Western states on more than 3,000 patients hospitalized for COVID-19 between Oct. 1, 2021, and July 26. All patients had either two or three doses of a COVID-19 vaccine. Eighty-one percent of participants were hospitalized when omicron was the dominant variant.
Booster vaccination was associated with decreased odds of hospitalization.
"This research shows us that even if you're fully vaccinated, there's a real value to getting a booster," said Ari Robicsek, MD, chief medical analytics officer at Providence and senior author of the study. "Compared to people who only had their initial vaccinations, people with boosters were a lot less likely to have severe Covid for 4-5 months after the booster shot."
Noted limitations of the study included possible booster vaccination at outside facilities and misclassification of cases or controls.