Study: Pfizer vaccine 88 percent effective against delta variant


Two doses of the Pfizer COVID-19 vaccine are 88 percent effective against the delta variant, according to a new study. 

The study, published in the New England Journal of Medicine on Wednesday from researchers at Public Health England, offers reassurance about the effectiveness of the vaccines against the delta variant. 

The 88 percent effectiveness against the delta variant was only modestly lower than the 93.7 percent effectiveness against the alpha variant, which was first identified in the United Kingdom. 

The findings reinforce earlier data from Public Health England in May finding 88 percent effectiveness against delta. 

They are in contrast to an Israeli study earlier this month that provoked some concern when it found the Pfizer vaccine was just 64 percent effective against the delta variant, but that study’s methods drew skepticism from some experts. 

The study published Wednesday also examined the AstraZeneca vaccine, which is in use in the United Kingdom but not in the United States. 

That vaccine was 67 percent effective against the delta variant, compared to 74.5 percent against alpha. 

Both vaccines were far less effective after only one dose, around 30 percent, leading officials to urge that people get both doses of the vaccine. 

The overwhelming message from health experts and officials in the U.S. is to get vaccinated, given that the vaccines have been found to offer protection even against the delta variant, which is now dominant in the U.S. and is fueling outbreaks among the unvaccinated given its transmissibility.

The 88 percent effectiveness of the Pfizer vaccine against delta is also against getting any symptoms. The effectiveness against hospitalization and death has been found to be even higher, though it was not measured in this study. 

“Vaccines work, even against variants,” tweeted Angela Rasmussen, a virologist at the University of Saskatchewan, in response to the new study. “Get vaccinated if you haven't already.”