As omicron subvariant BA.5 prompts a summer surge in COVID-19 cases, here are two recent studies on vaccine effectiveness against the quickly spreading variant:
1. The efficacy of primary vaccine doses have slightly decreased with each new variant the coronavirus cooks up, but booster doses are shortening that gap, according to research published July 19 in Science. The count of neutralizing antibody titers is the main metric for vaccine efficacy, and data indicates the amount of antibodies have waned with each new variant.
The study's results coincided with the trend but offered a reversal: With booster shots, the amount of neutralizing antibodies during the omicron subvariant BA.4/BA.5's reign increased.
People with one booster shot had neutralizing antibodies 12 times in BA.1 infections, eight times in BA.2 infections and seven times in BA.2.12.1 infections. Vaccine boosters increased antibodies 16 times in BA.4/BA.5 infections, the researchers found.
The results align with health experts' pleas to get boosted as soon as possible and not wait on the revised vaccine doses expected to debut this fall.
2. An analysis of COVID-19 infections between Jan. 21 and April 8 found that Pfizer's and Moderna's vaccines for children aged 5 to 11 are 82.7 percent effective at preventing hospitalization during the omicron surge.
The study, published July 20 in the New England Journal of Medicine, uncovered that overall vaccine efficacy for this age group was 13.6 percent after one dose and 36.8 percent after receiving a second dose.