Ministry data said to show Pfizer shot blocks majority of serious Delta cases

A study from researchers at Hebrew University and Hadassah University Medical Center suggest Pfizer and BioNTech's COVID-19 vaccine is 60% to 80% effective against infection from the Delta variant, reported The Times of Israel.

The news follows another report from Ynet, citing health ministry data, indicating that the mRNA-based vaccine, which has been the one used for almost all vaccinated Israelis, is significantly less effective against preventing the spread of the Delta variant, but appears to largely prevent hospitalization and serious cases.

According to the Ynet news site, over the past month, the vaccine was just 64% effective in preventing coronavirus infection, compared to efficacy of 94.3% during the month of May, when the strain was less prevalent.

However, the health ministry figures suggest that the vaccine retains potency against serious symptoms and hospitalization. During May, that efficacy figure stood at 98.2%, according to the data obtained by Ynet, and during June it was 93%.

Still, the researchers at Hebrew University warned that it was too early to fully tell how effective the vaccine is at preventing hospitalization.

"Due to the recognized delay in serious morbidity (by about 10 days), there is not currently enough data to predict how the current wave of infections will be expressed in serious cases," wrote the researchers.