Senior ICMR officials did not respond to calls from this newspaper seeking clarifications about how the ICMR expected the vaccine to be ready for launch by August 15. "Such an accelerated development pathway has not been done ever for any vaccine, even for the ones being tried out in other countries".

"The aim is to complete these phases at the earliest, so that population-based trials for efficacy could be initiated without delay", ICMR said in a statement. Although the launch of such a vaccine is the need of the hour, the announcement has drawn a lot of criticism from the scientific community.

"My understanding was that they wanted to get the first vaccines given in July, and they say they're still committed to do that", one investigator told STAT News.

"We must rush albeit carefully". Giving this project high priority is absolutely important.

Speaking to The Hindu, KGH Superintendent G. Arjuna said that the order has been communicated, but guidelines from the State government are awaited.

ICMR has developed the indigenous COVID-19 vaccine (BBV152 COVID vaccine) partnered with BBIL.

The chief of India's top clinical research agency said in a leaked letter circulated on Friday it envisaged launching a novel coronavirus vaccine by August 15, prompting scepticism from some health experts who questioned the short timeline.

What's more data about the vaccine's preclinical performance has not been made public yet.

"BBIL is using the virus strain isolated at the ICMR's National Institute of Virology, Pune, to develop the vaccine", said a scientist from the virology laboratory in KGH.

Covid 19 vaccine developers AstraZeneca, which is working with the University of Oxford, is already in Phase 3 of human trial - where a drug/vaccine is observed for therapeutic effect and adverse effects over a longer period than the previous phases - for its vaccine candidate.

The letter warned the 12 institutes that any non-compliance will be "viewed very seriously".

A copy of the letter has been sent to BBIL. Zydus is the second company in India to make a vaccine for the coronavirus indigenously. Dr Krishna Ella, Chairman and Managing Director of the company, has collaborated with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV) for developing the vaccine. However, Bharat Biotech is the first such firms to get the regulatory nod to begin phase 1 and phase 2 human trials. "After this, we will decide on releasing the vaccine".

"Based on in-depth scrutiny of the available data from pre-clinical studies, the Drugs Controller General of India has accorded permission to conduct phase 1 and 2 clinical trial", said the Council. Scientists working on it saw that it is safe and immunogenic in all animals. On Friday, Zydus said it has received approval from authorities to start human trials for ZyCoV-D.