Two shots of Pfizer or AstraZeneca vaccine are effective against Delta variant
pharmafile | July 22, 2021 | News story | Business Services, Manufacturing and Production, Medical Communications, Research and Development, Sales and Marketing |
A new study has shown that two shots of either Pfizer or AstraZeneca’s COVID-19 vaccine are nearly as effective against the Delta variant as they are against the previously dominant Alpha variant.
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.
However, one shot of the vaccine is not enough to offer high protection. It was recently reported that one shot of the J&J ‘one-shot vaccine’ is in fact not enough to offer protection against Delta.
The study found that two doses of Pfizer’s shot was 88% effective at preventing symptomatic disease from the Delta variant, compared to 93.7% against the Alpha variant.
Two shots of AstraZeneca vaccine were 67% effective against the Delta variant, up from 60% originally reported, and 74.5% effective against the Alpha variant, compared to an original estimate of 66% effectiveness.
Public Health England researchers wrote in the study: “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.
“Our finding of reduced effectiveness after the first dose would support efforts to maximise vaccine uptake with two doses among vulnerable groups in the context of circulation of the Delta variant.”
The full study published on Wednesday found that one dose of Pfizer’s shot was 36% effective, and one dose of AstraZeneca’s vaccine was around 30% effective.
The WHO has said that Delta, which first originated in India, would be the dominant strain in the world in the months to come.
Lilly Subbotin
