A large number of doctors, almost 50 per cent, feels that it was developed too quickly.

While Britain has already declined the superfast vaccine, WHO spokesperson Christian Lindmeirer has pointed out that there were established practices and guidelines that need to be followed while producing a vaccine.

“Any vaccine should go through various trials and tests before being licensed for a roll out,” the spokesperson said.

“Though individual researchers claiming that they have found something is great news, there is a great difference between finding or having a clue of having a vaccine that works and having something that has gone through all stages.”

Every vaccine needs to necessarily undergo three phases of human trials (where each phase takes several months to be completed) before the final stage in which a candidate vaccine is tested for its effectiveness in real-life situations, that is outside laboratory conditions.

Echoing the scientific community’s scepticism over Russia’s Covid-19 vaccine rolled out for emergency use, Nobel laureate Peter Charles Doherty says his “big worry” is that there could be refusals for other vaccines if doubts over its safety turn out to be true.

The Nobel laureate who is with the Department of Microbiology and Immunology at the Doherty Institute, University of Melbourne, also believes that India, “with its great track record in low-cost drug manufacturing can be a major player”.

Prime Minister Narendra Modi said during the 74th Independence Day speech three Covid-19 vaccines are being tested in India.

India’s first Covid-19 vaccine, Covaxin has been developed by Bharat Biotech, Indian Council for Medical Research and National Institute of Virology. Another vaccine has been developed by Zydus Cadila.