Prognosis

Single Pfizer Shot Cut 85% of Cases in Israel Health Workers

  • Researchers see big anti-Covid effect within weeks of dose one
  • Findings boost U.K. move to speed vaccination with first shot

A nurse handles a vial of the the Pfizer-BioNTech Covid-19 vaccine in Holon, Israel.

Photographer: Kobi Wolf/Bloomberg
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A single dose of the vaccine from Pfizer Inc. and BioNTech SE reduced Covid-19 infections by 85% in a study in Israel, bolstering the U.K.’s decision to speed immunizations by delaying a second shot.

Among health-care workers who got the vaccine, symptomatic infections were reduced by that percentage in the 15 to 28 days after the first dose, compared with those who didn’t get a shot, according to the report in The Lancet medical journal. While most workers received a second dose on schedule -- about three weeks after the first -- the booster would only have just started to kick in by the end of the study, so it was essentially looking at the effects of one dose, researchers said Thursday.