Chennai: Even as the Covid-19 vaccine is likely to arrive in Delhi by early next week, restricted emergency use of vaccines is considered based on safety and immunogenicity data, said Indian Council of Medical Research (ICMR) chief Balram Bhargava.
Explaining the process followed in granting nod to Oxford Covid-19 vaccine and indigenously developed Covaxin, he said, “The existing pandemic situation, high mortality, available science and lack of definitive treatments were considered by the subject expert committee (SEC) on Covid-19 of CDSCO for granting accelerated approval to these vaccines, and that is in our legal provision”.
The Drugs Controller General of India (DCGI) had on Sunday approved Oxford Covid-19 vaccine Covishield, manufactured by the Serum Institute, and indigenously developed Covaxin of Bharat Biotech for restricted emergency use in the country, paving the way for a massive inoculation drive.
Industry experts and some opposition leaders have expressed concern over the absence of Phase 3 trial data on Covaxin. The critics have cautioned that āsidesteppingā processes and giving āprematureā clearance could risk lives and fuel vaccine hesitancy in India.
“The SEC guides the DCGI in the process of decision making for restricted use under emergency situation. Now we have two vaccines,” Bhargava said.
Providing details of the UK studies of Covishield, the ICMR chief said animal studies showed that vaccine prevented SARS-CoV-2 pneumonia in monkeys and have elicited good immunogenicity in mice.
The Phase one and two clinical trials in 1,077 participants showed an acceptable safety profile, and homologous boosting increased antibody responses. Phase two and three in prime-boost regimen in 560 participants showed it was better tolerated in older adults than in younger adults and has similar immunogenicity across all age groups after a boost dose. The result was published in the Lancet, the ICMR chief said.
Phase 3 trial in 11,636 participants from UK and Brazil, with two standard doses, showed vaccine efficacy was 621 per cent, in case of a low dose followed by a standard dose, the efficacy was 90 per cent. Overall, Covishield efficacy was 704 per cent. This has been published online last month, he said.
As for Covishield’s phase two and three clinical trial in India, there were 1,600 participants aged than 18 years. Their immunogenicity data is being generated, more than half is available. Covishield is safe and immunogenic and the data showed that it is non-inferior to the UK product, Bhargava said.
“It was an important point that led to the approval,” he added.
As for Covaxin, Indian studies on animals such as rats, mice, rabbits, hamsters and monkeys showing excellent safety, immunogenicity. It showed robust viral clearance in both the upper and lower respiratory tract in large animals.