Israeli Study Finds Third Shot Provides Significant Boost in Covid-19 Immunity

When it comes to Covid-19 vaccinations, it appears the third time is a charm. A new Israeli study finds that people who get a third dose of the Pfizer-BioNTech vaccine have a significantly lower risk of infection from the coronavirus, including the more dangerous Delta variant.

A research team using data from Maccabi Healthcare Services in Tel Aviv found that the rate of infection dropped 48 to 68 percent within a week to 13 days after the third shot of the Pfizer vaccine. In addition, the study found the infection rate dropped even further—70 to 84 percent—two weeks to 20 days after the additional dose, reports Jason Gale of Fortune magazine.

Released on MedRxiv before submission to a peer-reviewed journal, the Israeli Ministry of Health study concludes there are short-term health benefits to receiving a third shot of the Pfizer-BioNTech vaccine.

“Further studies are needed to determine the duration of protection conferred by the third dose and its effect on severe disease,” conclude the researchers, who include Daniel M. Weinberger, an epidemiologist at the Yale School of Public Health.

So far, more than 2 million of Israel’s 9.3 million residents have received the third dose, reports Dov Lieber of the Wall Street Journal. They include 70 percent of Israelis 60 or older and about half who are more than 50 years old.

“If your goal is to provide someone with high levels of short-term immunity, there’s no question that a good way to do this is … through a booster shot,” David Dowdy, an epidemiologist at Johns Hopkins University, who was not involved in the research, tells Gretchen Vogel of Science magazine.

He cautions that more research is needed to find out how long the boosters last since this study only covers a short period of time.

Health officials in Israel also want to know more about the booster’s longevity. They say they don’t know yet if more than three doses will be needed to protect people, though they are moving ahead with plans to give the booster to as many people as possible as the Delta variant continues to spread.

The World Health Organization (WHO) had wanted wealthier nations to hold off on administering boosters until people in poorer countries had received their first shots. However, Hans Kluge, WHO Europe’s regional director, is now saying the additional dose should be given to people who are most at risk.

“A third dose of vaccine is not a luxury booster taking away from someone who is still waiting for a first jab,” he tells Hannah Knowles and Lenny Bernstein of the Washington Post. “But it’s basically a way to keep the people safe, the most vulnerable. But at the same time, we need to share. So we need to do it all.”

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David Kindy is a former daily correspondent for Smithsonian. He is also a journalist, freelance writer and book reviewer who lives in Plymouth, Massachusetts. He writes about history, culture and other topics for Air & Space, Military History, World War II, Vietnam, Aviation History, Providence Journal and other publications and websites.