Pfizer and BioNTech’s Covid-19 vaccine is just 39% effective in Israel where the delta variant is the dominant strain, but still provides strong protection against severe illness and hospitalization, according to a new report from the country’s Health Ministry.
The efficacy figure, which is based on an unspecified number of people between June 20 and July 17, is down from an earlier estimate of 64% two weeks ago and conflicts with data out of the U.K. that found the shot was 88% effective against symptomatic disease caused by the variant.
However, the two-dose vaccine still works very well in preventing people from getting seriously sick, demonstrating 88% effectiveness against hospitalization and 91% effectiveness against severe illness, according to the Israeli data published Thursday.
“We have to be mindful that, with time, the effectiveness of these vaccines may wane,” said Dr. Isaac Bogoch, an infectious disease professor at the University of Toronto.
The report out of Israel, which began vaccinating its population ahead of many other countries, is likely to bolster arguments from drugmakers that people will eventually need to get booster shots to protect against emerging variants.
Pfizer said earlier this month it is starting to see waning immunity from its two-dose vaccine, and now plans to seek authorization from the Food and Drug Administration for a booster dose. However, federal officials say fully vaccinated Americans do not need additional shots at this time.
In a statement to CNBC, Pfizer said it remains confident its two-dose regimen is protective against the coronavirus and its variants.