"94% decrease in symptomatic infection in vaccinated individuals" Israel today

According to data from the Clalit Research Institute, the effectiveness of the corona vaccine is maintained in all age groups • Prof. Blitzer: "With the help of the vaccines, dealing with a serious illness is avoided"

Clalit Research Institute today (Sunday) published the results of a study conducted on the effectiveness of corona vaccines, among 1.2 million vaccinated and non-vaccinated, which shows that among vaccinated there was a 94% decrease in symptomatic infection and a 92% decrease in severe disease compared to similar unvaccinated insured.

Vaccine efficacy is maintained in all age groups, including those aged 70 and over, an age group in which vaccine efficacy could not be evaluated in clinical trials due to its limited scope.

Photo: Moshe Ben Simhon, Newsenders

The researchers reviewed data from about 600,000 vaccinators aged 16 and over, of whom about 170,000 were vaccinated over the age of 60 and about 430,000 vaccinated between the ages of 16-59.

The vaccinated group was tested against a control group so that each vaccinated was tested in relation to an unvaccinated person similar to him in a long series of indicators such as: the level of risk of infection, the level of risk of developing a serious illness, health status and more. 

The data indicate a high efficacy of the vaccine for a period of 7 days or more after the second dose ('fully vaccinated'), and add information on the prevention of severe coronary heart disease, a result that is rare in the Pfizer clinical trial. 

"These results are the first swallow in a series of research results that the institute completes to evaluate the effectiveness of the vaccine in various groups and descriptions," says Prof. Ran Blitzer, director of the Clalit Research Institute.

"For weeks we have developed tools and methods to deal with the many biases that characterize this type of evaluation research in data based on real-world data, while neutralizing biases as required from clinical research." 

"The trends we identify show that continued follow-up for additional weeks after the second dose will significantly increase the measured efficacy of the vaccine. In fact, on a 14-day or more post-second test, in an initial test, we identify even higher efficacy in preventing symptomatic and severe disease among vaccinated people. "At any age, we will soon be able to give an accurate estimate in this matter as well, in the same method, and we expect that the efficiency data will then be even higher," explains Prof. Blitzer.

In light of these results and their significance, and although research is still ongoing and further findings and detailed results will become available in the coming weeks, the publication of preliminary results at this stage is intended to emphasize to the unvaccinated population that the vaccine is highly effective and prevents severe morbidity. 

The researchers took part in this research: Dr. Noa Dagan, Dr. Noam Barda, Dr. Eldad Kaftan, Oren Miron, Shai Parchik, Prof. Mark Katz and Prof. Ran Blitzer of the Clalit Research Institute, as well as Prof. Miguel Hernan, Prof. Mark Lifshitz and Prof. Ben Rice of Harvard University.