Older Israelis who were offered booster shots of the Pfizer vaccine have reportedly been shown to have dramatically improved protection against COVID-19. Israel was one of the first countries in the world to achieve significant vaccine coverage, but it’s battling a surge of infections fueled by the more transmissible Delta variant as well as declining immunity for those already vaccinated. According to a Reuters report, a study from the Israeli Health Ministry shows that “protection against infection provided from 10 days after a third dose was four times higher than after two doses.” Protection against severe illness and hospitalization was “five or six times greater.” Israel started giving booster shots to over-60s in July and has now extended the program to over-40s—although the shots are only offered to those who received their second jabs at least five months ago.