TEL AVIV—A booster shot of Pfizer Inc. and BioNTech SE ’s Covid-19 vaccine provides good protection against severe illness from the Omicron variant, while those without a third shot are highly vulnerable, according to a new Israeli study.
The findings, similar to those announced last week by Pfizer, suggest countries worried about Omicron’s rapid spread will be able to defend their populations with continued inoculation.