Vaccine was 39% effective at reducing infection risk and 91% effective at preventing severe illness, Israel Health Ministry says
TEL AVIV—Data from Israel suggests Pfizer Inc.’s vaccine has become less effective in preventing infection of Covid-19 in recent weeks, although it remains a robust bulwark against serious illness as governments around the world scramble to respond to the rampant spread of a new Delta variant of the coronavirus
The findings, which are preliminary and based on a small sample, suggest that after two shots the vaccine was 39% effective at reducing the risk of infection and 40% effective at reducing the risk of symptomatic disease during a period when the Delta variant dominated cases in Israel, according to the country’s Health Ministry. The vaccine was 91% effective at preventing severe illness in the same period between June 20 and July 17, the ministry said.