The updated Covid-19 boosters are cutting the risk that a person will get sick from the coronavirus by about half, even against infections caused by the rapidly spreading XBB.1.5 subvariant. New studies, conducted by researchers at the US Centers for Disease Control and Prevention, are among the first looks at how the bivalent boosters have continued to work in the real world as the virus has evolved.
The data shows that the boosters are continuing to offer substantial protection against currently circulating variants. The near-real-time data was collected by the federally funded Increased Community Access To Testing program, which administers Covid-19 tests through pharmacies. It includes results for adults receiving tests at participating pharmacies from December 1 to January 13.
Of nearly 30,000 test results included in the analysis, more than 13,000 (47%), were positive for Covid-19. More people who tested negative had gotten an updated bivalent booster compared with those who tested positive. On average, people in the study who had not gotten a bivalent booster also had not had a dose of a Covid-19 vaccine in more than a year. That’s about the same as the national average, the study authors said. Their protection against illness was probably very minimal, they said.