Recent data from the Israeli Health Ministry shows the effectiveness of Pfizer-BioNTech’s Covid-19 vaccine has dropped in recent weeks. Two shots were found 64% effective in preventing symptomatic infection, compared to 94% earlier this year. But it remains 93% effective in preventing hospitalisation — down from 97% earlier.
The Delta variant is reportedly responsible for over 90% of recent cases in Israel, which lifted restrictions in June, although around 57% of the population is vaccinated.
The new data comes after research by Hebrew University found the Pfizer vaccine 70% effective against Delta. Last month, a study in The Lancet found that one dose of the vaccine offered only 32% protection against Delta, as against 79% against the original strain. Even after two doses, the level of neutralising antibodies was over five times lower against the Delta variant than the level against the original strain.
But other studies, including an analysis by Public Health England in June, agree that the Pfizer vaccine offers high protection from hospitalisation even against Delta.
Israel’s data is only based on “preliminary” figures, gathered between June 6 and early July. Ran Balicer, chair of Israel’s national expert panel on Covid-19, has said it is too early to precisely assess effectiveness against Delta.
A Bloomberg report said Pfizer spokesperson Dervila Keane has declined to comment on the data from Israel, but said evidence so far suggests the vaccine “will continue to protect against these variants”.
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The Israeli government plans a detailed study of vaccinated people to assess the efficacy of the Pfizer vaccine. Pfizer’s CEO Albert Bourla has said people may need a third dose within 12 months of the second.