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Effectiveness May Decline, Data From Israel Suggests

New data from Israel suggests that the effectiveness of the Pfizer-BioNTech SARS-CoV-2 vaccine against infection may have declined, though it still protects against severe disease, the New York Times reports.

Earlier this month, health officials in Israel reported 64 percent of vaccinated individuals were protected against infection during a Delta variant outbreak and 94 percent were protected against severe illness. The new numbers say that the vaccine was 39 percent effective in preventing infection between late June and early July — when the Delta variant became more common in Israel — while it was 95 percent effective against preventing infection between January and early April, the Times says. It notes that, for both timeframes, the vaccine was more than 90 percent effective in preventing severe disease.

The Times cautions that the study was small, and Haaretz notes that the data in the study could be skewed as many of the tests were carried out in virus hotspots and among the elderly. BioNTech CEO Ugur Sahin tells the Wall Street Journal that it appears that antibody titers do wane but that there is no evidence that cellular immunity falls.

This, the Times adds, feeds into questions of whether a vaccine booster might be needed, which US officials have said currently is not needed. Israel, Haaretz notes, has begun administering boosters to immunocompromised individuals.