A full course of the Pfizer-BioNTech vaccine is 64% effective at preventing symptomatic Covid-19 [from the Delta variant], according to an early study by Israel’s health ministry reported [July 5], much lower than previous estimates of nearly 90%.
The vaccine still appears to be highly effective, 93%, at preventing serious illness and hospitalization, the data shows, though this is also slightly lower than earlier studies suggested and for other variants.
Biotech firm Moderna, which is based on the same type of technology as Pfizer’s jab, said its vaccine remains effective against the Delta variant and that blood samples from fully vaccinated individuals show only a “modest reduction” in antibodies.
Early studies indicate the Johnson & Johnson vaccine, the third authorized for use in the U.S., is also effective against the variant, the company said, generating immunity lasting for at least eight months.
Studies from the U.K., where Delta accounts for practically all new cases of Covid-19, found the AstraZeneca vaccine to be about 60% effective at preventing symptomatic disease and around 90% effective at preventing hospitalization, a modest drop compared to the Alpha variant that previously dominated.