Israeli Data Shows Pfizer Vaccine Less Effective Against Delta Variant

According to data from Israel, the vaccine developed by Pfizer Inc. appears to be less effective at providing protection against infection caused by COVID-19’s Delta variant. However, it does show the capability of protecting against severe illness from this extremely contagious strain. 64% of the people who were inoculated were protected by the vaccine from infection after the Delta variant outbreak. Israel’s Health Ministry said that this had been 94% earlier. The ministry said that the vaccine had been 94% effective in the same period at preventing severe illnesses, as opposed to 97% before.

On Tuesday, an Israeli official said that the findings released by the health ministry were preliminary and were based on the data that was collected from June 6th till early July. A brief explanation had been released on Tuesday by the health ministry regarding their methodology and the data responsible for the findings. According to the ministry, they had calculated the vaccine’s efficacy percentage by analyzing the number of infections that had occurred amongst the inoculated, as compared to unvaccinated people during the same time period. They also accounted for influential factors, including age, week of the infection, and whether the individual was infected previously.

In the period when the Delta outbreak occurred in Israel, the new infections had been around 1,528 and 1,271 of these people had been fully vaccinated. Likewise, 27 of the 37 people hospitalized and 11 of the 17 people suffering from severe illness were fully vaccinated. A spokesperson for Pfizer said that they couldn’t comment over an unpublished survey, but did highlight a recent study indicating that the vaccine was effective against new strains. 

The findings in Israel come as new cases of the coronavirus increased on Tuesday to a seven-day average of 300 from 10 per day in the last month. In order to prevent another increase in infections, the government had reimposed the requirement for indoor masks late last month, along with other measures. The total population in Israel is around 9.3 million. Top Israeli officials also met on Tuesday for discussing enacting additional measures for stopping the spread of the Delta variant, which appears to be responsible for the new cases. 

In late June, the country’s government had expanded their vaccination campaign to 12 to 15-year-olds because a larger portion of infections appeared to be occurring in this age group. Jen Psaki, the White House Secretary, was asked about these findings, and she described them as preliminary. In comparison with global standards, the number of cases in Israel is quite low. According to data from the UK, vaccines are able to retain most of their potency against the Delta variant, particularly after two doses have been administered. The UK also seems to be experiencing an increase in infections due to this variant, but it hasn’t increased the number of deaths, or stretched hospitals to the same extent as before. 

England’s public-health agency believes that full vaccination using AstraZeneca or Pfizer reduces the risk of infection against Delta by 79%.