The US Centers for Disease Control and Prevention says the latest boosters appear to provide some protection against the new XBB-related subvariants of the Omicron coronavirus.
The fast-spreading Omicron XBB.1.5 subvariant is becoming increasingly dominant in the United States. The CDC estimated that it accounted for 49.1 percent of the infections in the week through Saturday.
The CDC conducted an analysis on people who had COVID tests from last month through January 13 to check how effective the latest boosters are.
It found that for those aged 18 through 49, the boosters were 49 percent effective at preventing infections against the XBB-related subvariants, including the XBB.1.5. This was in comparison to people who had not gotten the booster.
For those aged 50 through 64, they were 40 percent effective. The figure was 43 percent for those aged 65 and older.
Health authorities in the US began rolling out the updated boosters in September. The CDC says, "All persons should stay up to date with recommended COVID-19 vaccines, including receiving a bivalent booster dose when they are eligible."