But the vaccine remains highly successful at preventing severe illness and death, the ministry said.
Israel has fully inoculated about 60 percent of its population, the vast majority of whom received the Pfizer-BioNTech vaccine. Some health experts criticized the Israeli study, and warned against overreliance on a single study result, pointing to a number of factors — including testing patterns — that could have influenced the result in ways difficult to measure.
Nonetheless, a substantial documented drop in the vaccine’s protection level could have serious implications for countries betting almost entirely on mass immunization campaigns — as well as poorer nations that have barely started their own vaccine drives.
In Britain, where the variant accounts for at least 95 percent of new infections, government officials have admitted that cases will probably soar after remaining pandemic-related restrictions are lifted this month, despite the fact that more than 50 percent of the population has been fully vaccinated.
Officials maintain that high vaccination rates will keep hospitalizations and deaths low. In May, researchers affiliated with Public Health England found that two doses of the Pfizer-BioNTech vaccine were 88 percent effective against symptomatic illness caused by the delta variant.
“We will soon be able to take a risk-based approach that recognizes the huge benefits that the vaccines provide both to people who get the jab and their loved ones too,” British Health and Social Care Secretary Sajid Javid said Tuesday.
His opposition counterpart, Jonathan Ashworth, however, expressed fear that the vaccine wall the government was relying on to protect the country was “only half built.”
Katerina Ang in Singapore contributed to this report.