Pfizer Vaccine Less Effective Against Delta Infections but Prevents Severe Illness,


TEL AVIV—Data from Israel suggests Pfizer Inc.’s vaccine is less effective at protecting against infections caused by the Delta variant of Covid-19 but retains its potency to prevent severe illness from the highly contagious strain.

The vaccine protected 64% of inoculated people from infection during an outbreak of the Delta variant, down from 94% before, according to Israel’s Health Ministry. It was 94% effective at preventing severe illness in the same period, compared with 97% before, the ministry said.

An Israeli official said Tuesday the health ministry findings released a day earlier were preliminary and based on data collected from June 6 through early July. The ministry didn’t release its methodology or the data on which its findings were based.

A spokesman for Pfizer said he couldn’t comment on an unpublished survey, but pointed to a recent study that showed the vaccine continued to offer protection against new variants.

The findings came as new cases of Covid-19 in Israel rose to a seven-day average of 300 on Tuesday from around 10 a day for most of last month. To prevent another surge in infections, the government late last month reimposed an indoor mask requirement and other measures after finding that about 90% of the new infections were likely caused by the Delta variant. Israel’s total population is around 9.3 million.

Read More:Pfizer Vaccine Less Effective Against Delta Infections but Prevents Severe Illness,

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