The third vaccine dose against COVID-19 increases the immune protection from infection tenfold, the Israeli Ministry of Health said on Thursday.
The ministry said that a new Israeli study, published in the New England Journal of Medicine, examined the effectiveness of the third dose among those over the age of 60, who received the booster shot in August. The tenfold protection is compared to those who received only two doses at least five months ago.
The study was conducted by a team of multidisciplinary researchers from the health ministry, the Weizmann Institute of Science, the Hebrew University of Jerusalem, the Technion, the Sheba Medical Center and the KI Research Institute, it said.
"The data from Israel indicate high efficacy of Pfizer's third booster dose in preventing COVID-19 infection and serious illness," the ministry noted, reports Xinhua.
Israel began vaccinating its population with the third vaccine dose on August 1, as the Delta variant was spreading in the country and the effectiveness of the first two doses eroded. To date, nearly 3 million Israelis have received the third jab.
The researchers found that 12 days after receiving the third shot, the rate of infections was more than 10 times lower among those who received the booster shot than those did not.
This means that if the chance of those vaccinated with two doses to get infected with the Delta variant is about 50 per cent compared to the unvaccinated, a booster dose lowers the risk to 5 per cent, or raises the immune defense to 95 per cent, the researchers concluded.