The Pfizer-BioNTech and AstraZeneki vaccines are almost as effective against the now dominant Delta variant of the SARS-CoV-2 coronavirus as before, against the Alpha variant, researchers from Public Health England (PHE), a UK government agency at the Ministry of Health, said.
“There were slight differences in vaccine efficacy for the Delta variant compared to the Alpha variant after receiving two doses,” the researchers wrote in an article published Wednesday in the New England Journal of Medicine.
They also noted that one dose of the Pfizer and AstraZeneki vaccines did not provide sufficient protection.
PHE on the effectiveness of the Pfizer and AstraZeneki vaccines
The effectiveness of two doses of Pfizer-BioNTech vaccine in preventing disease symptoms caused by the Delta variant was estimated to be 88 percent, compared with 93.7 percent against the Alpha variant.
Two doses of Oxford-AstraZeneca are expected to be 67 percent effective against the Delta variant. Previously, it was rated a little lower, at 60 percent. This vaccine is expected to be 74.5 percent effective against the Alpha variant.
Previously, PHE estimated that a single dose of the vaccine from both manufacturers was 33 percent effective against the Delta variant. It is now rated 36 percent for Pfizer and 30 percent for AstraZeneka.
Main photo source: Andrzej Grygiel / PAP