The scientists found that the Omicron-adapted shot also reduced mortality rates.
Researchers in Israel found an 81% reduction in hospitalizations among individuals aged 65 years and older who had received the Omicron-adapted booster shot by Pfizer and BioNTech compared to people who only received two COVID vaccinations.
The adapted bivalent booster targets the original virus that causes COVID-19 and its Omicron BA.4/BA.5 subvariant.
The researchers from Ben-Gurion University of the Negev, Sapir College, and health provider Clalit examined 622,701 adults aged 65 and older from September to mid-December. Among the participants, 85,314 had received the booster.
According to a news report, COVID-19 hospitalization occurred in 6 people who received the bivalent booster and 297 individuals who did not receive the shot. Moreover, one booster recipient died due to COVID — while 73 COVID-related deaths occurred in those who did not receive the booster.
In addition, researchers found that the lower hospitalization and mortality rates lasted up to 70 days after receiving the shot.
In the study, which has yet to be peer-reviewed, the scientists note that the drop in mortality rates is significant but statistically borderline because the death rate in Israel is relatively low.
According to the CDC, the adult dosing schedule for the Pfizer-BioNTech vaccine starts with a first dose, followed by a second dose 3–8 weeks later. They recommend receiving the updated bivalent booster at least two months after the second shot.
As of January 5, 2023, there were 628 counties, districts, or territories in the U.S. with high COVID-19 activity, 1,351 with medium activity, and 1,241 with a low activity level. The Omicron sub-variant BQ.1.1 is the most prevalent as of January 7, 2023.
However, the CDC is watching XBB.1.5 — a new rapidly-spreading COVID variant — and will continue investigating how it differs from other Omicron sub-variants.