Pfizer vaccine effective at halting spread, study finds

The Pfizer Inc. and BioNTech SE COVID19 vaccine appeared to stop the vast majority of recipients in Israel from becoming infected, providing the first realworld indication that the immunization will curb transmission of the coronavirus.

The vaccine, which was rolled out in a national immunization program that began Dec. 20, was 89.4% effective at preventing laboratoryconfirmed infections, according to a copy of a draft publication that was posted on Twitter and confirmed by a person familiar with the work. The companies and Israel’s Health Ministry worked together on the preliminary observational analysis, which has not yet been peerreviewed.

The results are the latest in a series of positive data to emerge out of Israel, which has given more COVID19 vaccines per capita than anywhere else in the world. Nearly half of the population has had at least one dose of vaccine. Separately, Israeli authorities on Saturday said the PfizerBioNTech shot was 99% effective at preventing deaths from the virus.

The early results on labconfirmed infections are important because they show the vaccine may also prevent asymptomatic carriers from spreading the virus that causes COVID19, something that hadn’t been clear so far. Stopping transmission in this way is a key factor as countries seek to lift contact restrictions and reopen economies.

Pfizer, headquartered in New York City, and BioNTech, based in Germany, said they are working on a realworld analysis of data from Israel, which will be shared as soon as it’s complete.

Fourfifths of the virus cases in Israel during the time period of the study, from Jan. 17 to Feb. 6, were the more transmissible strain first identified in the U.K. Israel’s vaccination drive began just before the B.1.1.7 variant emerged, fueling infections and leading to a third lockdown on Jan. 8.

Through Feb. 6, about 27% of people aged 15 and older in Israel were fully vaccinated, with the PfizerBioNTech shot the only vaccine available in the country at the time. People were considered fully vaccinated and included in the analysis if the data collected were more than 7 days after they received their second dose.