Pfizer shot found to be 94% effective in real world

JERUSALEM: The first big realworld study of the PfizerBioNTech vaccine to be independently reviewed shows the shot is highly effective at preventing Covid19, in a potentially landmark moment for countries desperate to end lockdowns and reopen economies.

Until now, most data on the efficacy of Covid19 vaccines has come under controlled conditions in clinical trials, leaving an element of uncertainty about how results would translate into the real world with its unpredictable variables.

The research in Israel — two months into one of the world’s fastest rollouts, providing a rich source of data — showed two doses of the Pfizer shot cut symptomatic Covid19 cases by 94% across all age groups, and severe illnesses by nearly as much.

The study of about 1.2 million people also showed a single shot was 57% effective in protecting against symptomatic infections after two weeks, according to the data published and peerreviewed in The New England Journal of Medicine yesterday.

The results of the study for the Clalit Research Institute were close to those in clinical trials last year which found two doses were found to be 95% effective.

‘‘We were surprised because we expected that in the realworld setting, where cold chain is not maintained perfectly and the population is older and sicker, that you will not get as good results as you got in the controlled clinical trials,’’ senior study author Ran Balicer said. ‘‘But we did and the vaccine worked as well in the real world.’’

The study also suggested the vaccine was effective against the Covid19 variant first identified in the United Kingdom.

Researchers said they could not provide a specific level of efficacy, but the variant was the dominant version of the virus in Israel at the time of the study.