Two doses of Covishield and Pfizer Covid-19 vaccines may be 90 per cent effective at preventing deaths from the Delta variant of the SARS-CoV-2 virus, according to a study published in the New England Journal of Medicine on Thursday. The study, using data from the Scotland-wide EAVE II Covid-19 surveillance platform, is the first to show across an entire country how effective vaccines are at preventing death from the Delta variant, the dominant form of the virus in many other countries.

The research team from Universities of Edinburgh and Strathclyde and Public Health Scotland analysed data from 5.4 million people in Scotland between April 1 and September 27, 2021. During this period, 1,15,000 people tested positive for Covid-19 through a PCR test conducted in the community, rather than in hospital, and there were 201 deaths recorded due to the virus. The study found that the Pfizer-BioNTech vaccine is 90 per cent effective and the Oxford-AstraZeneca vaccine, known as Covishield in India, is 91 per cent effective in preventing deaths in people who have been double vaccinated, but who have tested positive for coronavirus in the community.