The preventive efficacy of the Pfizer vaccine, which had reached 94% against the existing novel coronavirus, was much lower after the spread of the delta mutation, Israeli media YNet reported, according to a study.



According to statistics released by the Israeli Ministry of Health, from May 2 to June 5, the Pfizer vaccine was 94.3% effective in preventing COVID-19.



However, the preventive efficacy of the Pfizer vaccine, which was confirmed clinically between June 6 and March 3, fell to 64%.



In a comparison over the same period, Pfizer's vaccine's efficacy in severe prophylaxis fell from 98.2% to 93%, Wynet added.



About 55% of new infections during this period were 'breakthrough' cases of people who had been vaccinated, and the other half were from students with low vaccination rates.



The first confirmed introduction of a delta mutation in Israel was on April 16.



Since then, the delta mutation has spread rapidly among the unvaccinated.



According to the daily Haretz, about 90% of new infections in Israel are due to delta mutations.



Under this situation, Israel has lifted most of the quarantine measures from June 1, and also lifted the duty to wear indoor masks on June 15.



However, since then, cluster infections have occurred centered on schools where children and adolescents under the age of 16 who have not been vaccinated live, and in the end, more than 300 new confirmed cases per day have been recently reported.



In the midst of the spread of the delta mutation, which reduces the efficacy of the vaccine, the complete release of quarantine measures can be considered the cause of the re-spreading of the infection.



"I am concerned that the vaccine appears to be less effective [for delta mutations]," a senior Israeli Ministry of Health official said.



However, in a recent study jointly conducted by the Hebrew University and Hadsha University Medical Research Institute, the efficacy of the Pfizer vaccine in preventing delta mutation was found to be 60 to 80%.



Some experts have been somewhat cautious about the findings of this study.



"It can be seen that the vaccine's preventive efficacy against mild infections is low due to the high breakthrough infection rate, but it is still too early to accurately estimate the preventive efficacy of the delta mutation," said Lan Valeser, chair of the Israeli government's COVID-19 advisory committee. .



Balliser also said Israel's vaccine barrier could help mitigate the further spread of infection, and the fact that there were no deaths in the past 12 days is encouraging.



Meanwhile, Israeli Prime Minister Naftali Bennett ordered the Ministry of Health to conduct research necessary for important policy decisions, such as the third vaccination.



The two studies, overseen by a public health service officer under the Ministry of Health, are the long-term efficacy of vaccines in different age groups and the effect of cell-mediated immunity (T-cell-mediated host defense).



However, the Ministry of Health drew a line that there is no recommendation or decision for booster vaccination for the general public at this time.