COVID-19 vaccine
COVID-19 vaccineiStock

An Israeli study published on Wednesday in the New England Journal of Medicine finds that a third dose (booster) of the Pfizer coronavirus vaccine reduces the risk of COVID-related death by 90 percent.

The study was conducted by the Clalit Health Services Health Maintenance Organization, together with the Maximizing Health Outcomes Research Lab at Sapir College in Sderot and the Faculty of Health Sciences at Ben-Gurion University of the Negev in Be’er Sheva.

The study, which was conducted on people aged 50 and older, followed up on clients from all HMOs who received the second dose of the vaccine at least five months earlier, and compared the fatality rates from COVID-19 among the group that received the booster shot to the group that did not.

The study was conducted during the Delta variant wave, between August 6, 2021 (a week after the booster shot was approved for adults in Israel) and September 29, 2021.

The researchers surveyed the data on 843,208 Clalit members age 50 and up who received the second dose of the vaccine.

The methods for the study included monitoring two groups, in which those who receive the booster are then moved from the two-dose group to the three-dose group. The average age of the group in the study was 68.5, and at the end of the period of the study, 90 percent of this group had received the third dose of the vaccine.

The study found that among those who received the booster – starting from a week after the shot – the fatality rate from COVID-19 fell by 90 percent. Among men, it fell by 88 percent and among women it fell by 94 percent, compared to the group that received only the first two doses.

“The results of the research that we conducted unambiguously show that the booster vaccine is clearly correlated with a reduction in the risk of death from COVID, including the Delta variant. There are very few interventions in the medical world that can be attributed with a tenfold reduction in the risk of death, as we found for the booster vaccine,” said Dr. Doron Netzer, Clalit’s head of community medical services.