The bivalent boosters were just 43% effective at preventing mild illness compared to receiving no vaccine in adults 49 and under, according to a US Centers for Disease Control and Prevention study published Tuesday. In those aged 50 to 64 years, comparative protection against symptomatic Covid was 28%, while the booster was just 22% protective in adults 65 and older, the study showed.
- One month after a 30-µg booster dose of the Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine, neutralizing antibody titers against emerging Omicron sublineages increased 3.2- to 4.8-fold compared to the companies’ original COVID-19 vaccine
- Neutralizing antibody titers against Omicron sublineages BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1 increased 4.8- to 11.1-fold from pre-booster levels, following a 30-µg booster dose of the bivalent vaccine
More adverse reactions following bivalent COVID-19 mRNA booster vaccine