Clalit Research: Booster vaccination reduces serious illness by 92% and hospitalizations by 93%

A study by the Clalit Research Institute and Harvard University, published tonight (Saturday) in the journal Lancet, shows that the third dose of the vaccine, the booster, reduces hospitalizations by 93%, serious illness by 92% and mortality by 81%.
The study was conducted between July 30 and September 23 this year and compared 728,321 Clalit patients who received a third dose of vaccine, and the same number of patients who received only two doses about five months earlier.
"The study included another analysis, at the population level, that found that in each age group, infection rates began to decline one to ten days after the group became eligible for the third dose," the researchers said. "The correlation between the results of this analysis and the results of the main analysis, performed by different methods and with different resolution (individual patient level versus population level), increases the certainty that the study findings are accurate."
Prof. Ran Blitzer, Head of Innovation at Clalit and Director of the Clalit Research Institute, explained: For anyone who is still hesitant about receiving the third dose - in Israel and other countries. "
Another recent study by the Clalit Research Institute and Harvard University found that teens between the ages of 12 and 18 who received a Pfizer vaccine against corona had a 90% efficacy in preventing infection and a 93% efficacy in the onset of symptomatic disease. The study was conducted during the fourth wave of the corona, between June 8 and September 14. It was based on data from 94,354 Israeli youths who were vaccinated, compared with the same number of unvaccinated people, although during the study about 14,000 boys from the second group were vaccinated.
"With the outbreak of the fourth wave, due to the Delta strain, the question arose as to whether the vaccine used in Israel also provides adequate protection against this strain, as it protected against the alpha strain," said Prof. Blitzer. "Because most adolescents were first vaccinated in this wave, evaluating the effectiveness of the vaccine in them could provide an answer to the question. The results of the study unequivocally show that the vaccine is most effective in preventing Delta strain infection and preventing symptomatic disease one week after receiving two doses.
"The results of the study show that the potency of protection against the Delta strain is very similar to that observed in young adults against the alpha strain in the past. These findings provide important and well-founded information for parents who are undecided about vaccinating their adolescent children."