Pfizer’s updated bivalent COVID-19 vaccines (NYSE:EFPInc/BioNTech SE and Moderna helped prevent symptomatic infections with XBB omnin subvariants, according to an analysis by the U.S. Centers for Disease Control and Prevention released Wednesday.
The analysis revealed that the updated vaccine, targeting the BA.4 and BA.5 variants of omicron and the original strain of virus, helped prevent illness in people who had previously received two to four doses of the original COVID-19 vaccine, the CDC said.
The analysis took into account cases recorded between December 1 and January 13, a period of time when the circulation of XBB and XBB.1.5 increased in the United States. The subvariants are descendants of omin, the most contagious variant of the virus that causes COVID-19.
CDC noted that the updated vaccine worked similarly against BA.5-related and XBB/XBB.1.5-related infections. It was 52% effective in preventing infections against BA.5 and 48% against XBB/XBB.1.5 among people aged 18 to 49 years. Efficacy decreased to 37% versus BA.5 and 43% versus XBB/XBB.1.5 among those over 65 years of age.
The CDC also noted that the study shows how vaccines work at the population level, but that individuals may not see the same benefit. The CDC notes that people should be up-to-date on recommended COVID-19 vaccines.
The XBB.1.5 virus is estimated to have accounted for nearly half of U.S. cases in the week ending Jan. 21, according to government data.
The CDC’s analysis comes ahead of a meeting Thursday at which experts outside the Food and Drug Administration are expected to discuss whether and how the U.S. should offer the COVID vaccine as an annual shot.