Pfizer-BioNTech COVID-19 booster improves vaccine effectiveness, study finds

Feb. 14 (UPI) -- The Pfizer-BioNTech COVID-19 vaccine booster improves full vaccination effectiveness for warding off infection and hospitalization after one month, a new study shows.

The Kaiser Permanente study published Monday in The Lancet Regional Health Americas found effectiveness for preventing infection and hospitalization of the booster or third dose of vaccine was higher than that seen one month after receiving full vaccination or two doses.

After two doses, vaccine effectiveness of 85% during the first month declined to 49% seven months or more after vaccination, but effectiveness against hospitalization was 90% and did not wane, except in immunocompromised individuals and those over age 75.

In immunocompromised individuals, the protection against hospitalization decreased to 74% seven months after full vaccination, and in individuals age 75 and older, it was 77%.

The third dose booster effectiveness was 88% against infection and 97% against hospitalization within the first three months after vaccination.

"What we see from this research is that the public health impact of a third dose to prevent severe disease is substantial," said Sara Y. Tartof, an epidemiologist with the Kaiser Permanente Southern California Department of Research and Evaluation, in a statement.

The study evaluated electronic health records of 3.1 million members of Kaiser Permanente Southern California from Dec. 14, 2020, and Dec. 5, 2021. During the study, 197,535 (6.3%) patients had COVID-19 diagnosis, and of those, 15,786 (8%) were admitted to the hospital.

The predominant variant during the study period was Delta, not Omicron.

Last month, researchers found that antibodies that can counter the Omicron variant are still present in the body four months after the Pfizer booster shot, in a preliminary report from scientists working for the vaccine maker and the University of Texas Medical Branch.

Also, last month, Pfizer announced it launched a study on a COVID-19 vaccine tweaked to fight Omicron variant, and the next day Moderna announced it had launched a similar trial.

Another study on the Pfizer-BioNTech vaccine published last week in JAMA Pediatrics found that pregnant people who receive the COVID-19 vaccine during their first or second trimester are not at risk for preterm delivery or other birth complications.

In December, a Johnson & Johnson study found its booster shot was 85% effective against preventing COVID-19 related hospitalizations.

The same month Moderna announced that preliminary data show its booster shot significantly increases the number of disease-fighting antibodies against the Omicron variant compared to fully vaccinated persons who have not received the third dose.