Israel's Ministry of Health says the Pfizer-BioNTech vaccine isn't offering the same level of protection against COVID-19 now that the Delta variant is dominant. In May, when the Alpha variant dominated Israel, the vaccine was found to be 95.3% effective against infection, per CNN. But in a brief Monday statement, the ministry describes a "marked decline" in the efficacy of the vaccine in preventing infection and symptomatic illness down to 64% as of June 6, per NPR. The implication is that the risk of fully vaccinated people becoming sick has increased significantly, reports NPR health correspondent Rob Stein. The government attributes this to a rise in cases caused by the more contagious Delta variant, which has "near-total dominance in Israel," per the New York Times. However, no details about the analysis were released and experts are urging caution.
Several studies looking at the effectiveness of vaccines against the Delta variant have come up with different figures. An English study published in May found the Pfizer vaccine was 88% effective against symptomatic disease from Delta, compared to 93% effective with the Alpha variant. A Scottish study published in June found the Pfizer vaccine was 79% effective against Delta, compared with 92% against Alpha. And a Canadian study published Saturday found the Pfizer vaccine was 87% effective against Delta. All of these taken together "are probably more likely to be correct than the one," Harvard epidemiologist Marc Lipsitch tells the Times, though the outlet notes Israel may be finding more asymptomatic cases through its testing policies. On the bright side, studies—including this one—show most vaccines are highly effective at preventing severe disease with Delta. (Read more COVID variants stories.)