The news came as India’s attempt to launch a Covid-19 vaccine by August 15 was met with scepticism by some scientists, who questioned whether a vaccine can be pushed for public use after barely a month of trials.

The Indian Council of Medical Research (ICMR) – India’s premier biomedical research body – has announced a Covid-19 vaccine for public use by August 15, India’s independence day. 

Dr Balram Bhargava, director general of the ICMR, sent a letter to 12 hospitals selected for the clinical trial of Covaxin, telling them that development of the vaccine should be seen as a top priority project. 

The letter says the vaccine’s development is being monitored at the highest government levels. The trials are ordered to start no later than July 7.

The vaccine is derived from a strain of Sars-CoV-2 isolated by ICMR’s National Institute of Virology in Pune.

However, the ICMR has come under criticism from scientists, who say the deadline is “impossible” to meet and could put intense pressure on regulators to approve the vaccine before it has been fully vetted.

The head of one of the 12 institutes contacted by the ICMR, speaking on condition on anonymity, told The Daily Telegraph: “This is just impossible. We can’t do it by August 15. I’m sure ICMR doesn’t mean it.”

Dr Amit Suresh Bhate, Jeevan Rekha Hospital in southern Indian state of Karnataka, which is one of the 12 institutes, said: “We have not started the vaccination. We are yet to receive the vaccines. We don’t know whether we will be able to meet the deadline.”

He added: “It’s a very short period… but we will try our best to finish the trials as soon as possible.”

Dr Anant Bhan, a bioethics researcher, said: “It looks highly impossible to get all of the vaccine development phases done by August 15. To my knowledge, such an accelerated development pathway has not been done ever for any kind of vaccine, even for the ones being tried out in other countries.

“Even with accelerated timelines, this seems really rushed, and hence with potential risks, inadequate attention to process.”