Research published in the New England Journal of Medicine on Wednesday showed that the vaccines were very effective against the Delta variant, now the dominant strain in the world, provided a person received two injections.
The study confirms the main results given by Public Health England (PHE) in May on the effectiveness of COVID-19 vaccines manufactured by Pfizer-BioNTech and Oxford-AstraZeneca based on real world data.
Wednesday’s study found that Pfizer was 88% effective at preventing symptomatic Delta variant disease with both doses, compared to 93.7% against the Alpha variant, roughly the same as before.
Two AstraZeneca vaccine injections were 67% effective against the Delta variant, compared to 60% initially reported, and 74.5% against the Alpha variant, against an original estimate of 66% effectiveness.
“Only modest differences in vaccine efficacy were noted with the Delta variant versus the Alpha variant after receiving two doses of the vaccine,” the researchers from Public Health England wrote.
Data from Israel estimated that Pfizer’s vaccine is less effective against symptomatic illnesses, although protection against serious illness remains high.
PHE had previously stated that the first dose of either vaccine was about 33% effective against symptomatic Delta variant disease.
Other vaccines that are also useful
The full study published Wednesday found that one dose of Pfizer’s vaccine was 36 percent effective and one dose of AstraZeneca vaccine was about 30 percent effective.
“Our finding of reduced efficacy after the first dose would support efforts to maximize vaccine uptake with two doses among vulnerable groups in the context of the Delta variant circulation,” the study authors said. .
Recently, researchers at Beth Israel Deaconess Medical Center in the US city of Boston also said that in the lab, the antibody response of the single-dose Johnson & Johnson vaccine worked well against Delta, and the immune response lasted for about eight months. .
In June, the makers of the Russian vaccine Sputnik also said it was around 90% effective against the highly contagious Delta variant.
The vaccine, which Russia has actively marketed overseas, has already been found by researchers to be nearly 92% effective against the original strain of coronavirus.
Denis Logunov, deputy director of the Gamaleya Institute in Moscow which developed Sputnik, said the efficacy figure for the Delta variant was calculated based on digital medical and vaccine records, the state news agency reported. Russian RIA.
The Sputnik vaccine, however, has generated some controversy as it was introduced to the public even before a full trial was completed. It is still awaiting approval from the World Health Organization.