Pfizer, AstraZeneca Covid vaccines less effective against Delta variant: Study
Deccan ChronicleLondon: The COVID-19 vaccines by Pfizer and AstraZeneca are less effective against the Delta variant of coronavirus compared to the Alpha variant, according to a study led by researchers at the University of Oxford. However, Delta infections after two vaccine doses had similar peak levels of virus as those in unvaccinated people, the researchers said. Two doses of Pfizer-BioNTech have greater initial effectiveness against new COVID-19 infections, but this declines faster compared with two doses of Oxford- AstraZeneca vaccine, they said. "The fact that we did not see any effect of the interval between first and second doses, and the greater effectiveness of having had two doses, rather than one dose, supports the decision to reduce this to eight weeks now Delta is the main variant of concern in the UK," said Koen Pouwels, senior researcher in Oxford University.