When the Omicron variant led to a global resurgence of Covid-19, Israel approved a fourth vaccine (second booster) for people 60 years of age and older who received the first booster dose four or more months earlier. Now, a study of 563,465 eligible 60- to 100-year-old members of Clalit Health Services, Israel’s largest HMO, shows that Covid-19 mortality among participants who received the second souvenir was 78% lower than participants who received it. only a booster dose. “The bottom line is that the second booster saves lives,” said Ronen Arbel, a Health Outcome Researcher at Clalit Health Services and Sapir College. A paper on the results is being considered for publication in the journal Nature Portfolio. Click here to read the preprint – a preliminary version of a manuscript that has not completed peer review. Authors include Arbel as well as staff from the Clalit Community Medical Services Department and Ben-Gurion University. Meanwhile, an article in the New England Journal of Medicine from Sheba Medical Center evaluating the effectiveness and safety of the second souvenir in healthy young health care workers concludes that it is safe but has “only marginal benefits”. “Together with previous data showing the superiority of a third dose over a second dose, our results suggest that maximal immunogenicity of mRNA vaccines is achieved after three doses and that antibody levels can be restored with a fourth dose. In addition, we observed low efficacy of the vaccine against infections in health care workers, as well as relatively high viral loads suggesting that those infected were contagious, the authors conclude, noting that the elderly and vulnerable populations were not evaluated.
