Two doses of Pfizer or AstraZeneca’s COVID-19 vaccine are nearly as effective against the highly transmissible Delta coronavirus variant as they are against the previously dominant Alpha variant, a study published on Wednesday showed.
The study, published in the New England Journal of Medicine, confirms headline findings given by Public Health England in May about the efficacy of COVID-19 vaccines made by Pfizer-BioNTech and Oxford-AstraZeneca, based on real-world data. Wednesday’s study found that two doses of Pfizer’s shot were 88 percent effective at preventing the symptomatic disease from the Delta variant, compared to 93.7 percent against the Alpha variant, broadly the same as previously reported.
Two shots of the AstraZeneca vaccine were 67 percent effective against the Delta variant, up from 60 percent originally reported, and 74.5 percent effective against the Alpha variant, compared to an original estimate of 66 percent effectiveness.
“Only modest differences in vaccine effectiveness were noted with the Delta variant as compared with the Alpha variant after the receipt of two vaccine doses,” Public Health England researchers wrote in the study.
The full study published on Wednesday found that one dose of Pfizer’s shot was 36 percent effective, and one dose of AstraZeneca’s vaccine was around 30 percent effective.
“Our finding of reduced effectiveness after the first dose would support efforts to maximize vaccine uptake with two doses among vulnerable groups in the context of circulation of the Delta variant,” the authors of the study said.
The study, published in the New England Journal of Medicine, confirms headline findings given by Public Health England in May about the efficacy of COVID-19 vaccines made by Pfizer-BioNTech and Oxford-AstraZeneca, based on real-world data. Wednesday’s study found that two doses of Pfizer’s shot were 88 percent effective at preventing the symptomatic disease from the Delta variant, compared to 93.7 percent against the Alpha variant, broadly the same as previously reported.
Two shots of the AstraZeneca vaccine were 67 percent effective against the Delta variant, up from 60 percent originally reported, and 74.5 percent effective against the Alpha variant, compared to an original estimate of 66 percent effectiveness.
“Only modest differences in vaccine effectiveness were noted with the Delta variant as compared with the Alpha variant after the receipt of two vaccine doses,” Public Health England researchers wrote in the study.
The full study published on Wednesday found that one dose of Pfizer’s shot was 36 percent effective, and one dose of AstraZeneca’s vaccine was around 30 percent effective.
“Our finding of reduced effectiveness after the first dose would support efforts to maximize vaccine uptake with two doses among vulnerable groups in the context of circulation of the Delta variant,” the authors of the study said.
