Covishield 90% effective if doses given after gap of 2-3 months: Adar Poonawalla

Serum Institute of India CEO Adar Poonawalla has said AstraZeneca-Oxford vaccine, which is manufactured by Serum in Pune, is 90 per cent effective provided there's a two-three month gap in jabs.

Poonawalla's comments are in contrast with The Lancet study published earlier this year, which found the vaccine to be 70 per cent effective against Covid-19. "One arm of trials, in which doses were given one month apart, was 60-70 per cent effective. And there was another group of a few thousand patients where they gave a gap of 2-3 months between the two doses. That is where they found the efficacy to be 90 per cent," Poonawalla said.

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"If you look at other vaccines as well, the long gap you keep between the doses, the better their efficacy," Poonawalla further said. Last month, the government had increased the gap between the two-dose regimen of Covishield after the recommendation of the National Expert Group on Vaccine Administration.

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The group had suggested increasing the gap after Covishiled trials conducted in other countries found that the vaccine efficacy was increased if the second shot was administered after six weeks of the first one. As per Poonawalla, the vaccine starts creating immunity a month after the first dose of the vaccine is administered.

"We found an excellent response below the age of 50 with one dose. We can say after a month, even with one dose, there is excellent protection, more than even what you find in a Covid-19 recovered patient. About 70 per cent of people are fully protected with one dose, but the second dose is necessary for long-term immunity protection," he said.

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Apart from Covishield, the company is working on the development of its own vaccine, Poonawalla had revealed earlier. He also said that trials for Covovax, a vaccine jointly to be developed by both SII and US-based biotechnology company Novavax, have also started in India. Adar said the vaccine has been tested against African and UK variants of COVID-19 and has an overall efficacy of 89 per cent. The vaccine is aimed to be launched by September 2021.

India has so far approved two vaccines against COVID-19 -- Covishield, manufactured by the SII, and the indigenously-developed Covaxin of Bharat Biotech -- for restricted emergency use in the country.

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