A fourth dose of the Pfizer/BioNTech vaccine boosts a person’s antibodies fivefold in the space of a week, a preliminary Israeli study shows, supporting the country’s decision to offer a second booster to high-risk groups.
The study is preliminary and has yet to be peer reviewed or published in a medical journal.
“This is good news,” said Prime Minister Naftali Bennett, who embraced the decision to recommend it. “That’s an indicator of a very high likelihood that the fourth dose will protect vaccinated people to a great degree against infection [and] to some degree against severe symptoms.”
Israel began rolling out a fourth shot of the Covid-19 vaccine to people 60 and older, as well as health care workers on Monday. Israel’s immunocompromised residents began receiving their second booster shot on New Year’s Eve. But this study, conducted at the Sheba Medical Center just outside Tel Aviv, used healthy hospital workers as their subjects.
Bennett’s spokesperson said the results increased the likelihood of a fourth shot being rolled out to the general population, though the final decision would lie with the Ministry of Health’s Director-General Nachman Ash.
Israel’s seven-day average of daily cases stands at 5,273, according to data compiled by Johns Hopkins University. The highest seven-day average was 9,426 between August and September last year.
Earlier in the week, Bennett predicted the country’s current wave could peak at 50,000 cases a day. The R-coefficient, the number of people infected by each person who tests positive, jumped to 1.91, a level not seen since June 2021.