Pfizer, AstraZeneca less effective against Delta Variant

It is a known fact that Covid-19 vaccines – Pfizer and AstraZeneca – are currently being administered in India.

Now, a recent study led by researchers at the University of Oxford has found that Pfizer and AstraZeneca are less effective against the Delta variant of Covid-19 compared to the Alpha variant.

However, the researchers have noted that both vaccines still offer good protection against new infections. Two doses of either Pfizer-BioNTech vaccine or Oxford-AstraZeneca preventive still gave at least the same level of the shield as having had the virus before through natural infection, they said.

The researchers analysed 2580,021 test results from the nose and throat swabs taken from 384,543 participants aged 18 years or older between December 1, 2020, and May 16, 2021. They also analysed 811,624 test results from 358,983 participants between May 17, 2021, and August 1, 2021.

“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,” researchers at Oxford University said.

The researchers also found that a single dose of the Moderna vaccine has similar effectiveness against the Covid-19 Delta variant as single doses of the other vaccines.