Coronavirus vaccine booster shots increase protection from infection over tenfold in those over 60, according to an Israeli study published Wednesday in the New England Journal of Medicine.
The study used data on 1.14 million Israelis aged 60 and up who had received two doses of the vaccine by the end of August. It divided cases into two groups: one consisting of people who received two doses of the vaccine, and another consisting of people who received a third dose. The researchers found that at least 12 days after the booster shot, the rate of infection in the non-booster group was 11.4 higher than the booster group, while their rate of severe illness was 19.5 times higher.
The peer-reviewed study was authored by 11 researchers, including Health Ministry director general Nachman Ash and Israel’s director of public health services, Dr. Sharon Alroy-Preis. They used several statistical methods and wrote that they had attempted to account as much as possible for variables such as behavioral differences and differences between different demographic populations.
The findings provide further evidence that immunity gradually wanes after the first two doses of the vaccine. In August, Gili Regev-Yochay, director of the infectious diseases unit at Sheba Medical Center, said that there is a "consistent decrease in the level of antibodies among all ages. We are seeing a drop of 90 percent within six months in both young people and older people. The difference is the starting point – the young begin with a higher level of antibodies, almost double as much as people aged 60 and up have.”
The New England Journal of Medicine published the study two days after an article in The Lancet said there was insufficient evidence that booster shots are necessary at this stage. The international group of scientists that penned the article argued that receiving two shots of a coronavirus vaccine still provides adequate protection.