A group of doctors and scientists on January 14 hit out at the critics of the government's approval to two COVID-19 vaccines, especially the one produced indigenously by Bharat Biotech, alleging that their "reprehensible" utterances are causing huge credibility crisis for the Indian scientific community.

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In a statement signed by 45 medical professionals and scientists, the group expressed shock at the "irresponsible statements of vested interests" and accused these critics of casting aspersions on Indian experts' integrity by making politicised statements to doubt the recent research in the field of COVID-19 vaccines.

The statement, whose signatories include former AIIMS directors T D Dogra and M C Mishra, former CSIR-IICT, Hyderabad, chief scientist A Gangagni Rao and Manipal Education and Medical Group's Chairman of Board Ranjan Pai, said these vaccines are our gift to the humanity.

India had recently approved two vaccines, Oxford-Astra Zeneca's Covishield being manufactured by Serum Institute of India and Bharat Biotech's Covaxin, for emergency-use authorisation. Some experts and a few opposition leaders had questioned the decision, noting that the phase three trial of Covaxin was not yet complete and its efficacy data was not available.

The government has insisted that it has followed all procedure. "We urge upon our fellow countrymen to reject the manipulations of vested interests aimed at politicisation and defamation of our nation's scientists, doctors and scientific community for their narrow vested interests. They need to realise that by doing so, these vested interests are wrecking the highly valued and credible scientific edifice created by us, which has made India a global leader in the export of vaccines all over the world," the statement said.

"Such reprehensible utterances are causing huge credibility crisis for the Indian scientific community who have devoted their lifetimes to make India a name to reckon with in export of vaccines all over the world," it added. The statement's signatories noted that India has emerged as a global leader in supply of vaccines to the world due to the efforts of its doctors and scientists.

Vaccines are exported from India to over 188 countries, and the Indian vaccine market reached a value of Rs 94 billion in 2019 and has still got unused potential for the future, they said. Defending the vaccines, they said Covaxin has been developed on 'Vero cell platform', which has a well established track record of safety and efficacy globally.

Phase I and Phase II clinical trials of Covaxin were conducted in approximately 800 subjects and the results have demonstrated that the vaccine is safe and provides a robust immune response, they noted and said more than 22,000 volunteers have been enrolled to determine its efficacy for phase three studies.

Though efficacy data is not available for Covaxin but safety parameters are very good, and there is a robust immune response seen with this vaccine, they said. "Further this vaccine is a whole virus inactivated vaccine which may have better protection even against mutant strains of the virus as the immune response will be against multiple antigens and not only against spike protein," the experts said.

They noted that Covishield still needs data from India on immunogenicity and efficacy but has been given emergency use authorisation keeping in mind the difficult times due to COVID pandemic. This vaccine has undergone phase I, II and III clinical trials of safety, immunogenicity and efficacy abroad, and its overall efficacy was found to be 70.42 per cent, they added.