Amid its efforts to accelerate the development of a vaccine against Covid-19, the Indian government is facing criticism for binding itself with a near-impossible deadline.

A letter from the Indian Council of Medical Research (ICMR) on July 2 said a locally developed vaccine - for which human trials are yet to start - is meant to be ready for public use by Aug 15.

This deadline is unusually tight, even against the accelerated timeline international vaccine initiatives have adopted amid the pandemic.

Some of the vaccine development efforts that began several months ago are in the third and final stage of testing on humans.

This institutional rush in India has alarmed many who fear it could lead to corners being cut, even compromising the vaccine's safety.

The ICMR, India's apex regulatory body for biomedical research, has partnered Bharat Biotech International Limited (BBIL) to develop the vaccine under the name Covaxin.

ICMR's letter was sent by its director-general Balram Bhargava to hospitals participating in phase one and phase two trials. The hospitals were asked to start enrolling participants "no later than July 7" and the vaccine was described as "one of the top priority projects which is being monitored at the top-most level of the government". It added: "Kindly note that non-compliance will be viewed very seriously."

This has prompted criticism from several quarters, including the Indian Academy of Sciences which described the announced timeline as "unfeasible" and "without precedent".

"This timeline has raised unrealistic hope and expectations in the minds of our citizens," it added in a statement on Sunday.

Dr Amar Jesani, editor of the Indian Journal of Medical Ethics, told The Straits Times that while one can speed up certain processes - such as regulatory reviews and recruitment of participants - scientific and ethical research standards must not be compromised.

"You cannot rush through the scientific and ethical process. If you do so, it is possible that your vaccine may fail or even cause more harm than benefit," he said.

According to ICMR's clinical trials registry, recruitment of participants was scheduled to start on July 13 and the entire duration of trials for Covaxin is listed as 15 months.

Dr Krishna Ella, BBIL's chairman and managing director, had even told Indian media last month that he expected phase one and phase two trials to finish by October this year.

Dr Jesani said: "How do you reduce a 15-month timeframe to one that is just a month and a quarter? There has to be a method in madness too. What happened with ICMR was that there was no method in its madness."

The letter's sternly worded directive, according to him, also risks compromising the independence of ethical and scientific review committees at the participating institutions. These committees are meant to independently approve the trial protocol and oversee its conduct.

The Aug 15 deadline has also raised eyebrows because it coincides with the date of India's independence, a day during which the prime minister traditionally lists the government's key achievements and priorities.

An indigenous vaccine, if available by then, will come in handy for the Narendra Modi-led government that is keen to convince the country that it has the pandemic under control.

India, in fact, has failed to slow down the outbreak despite a hastily imposed lockdown described as the world's strictest.

The country has registered more than 720,000 Covid-19 cases and is third on the list of countries with the most infections.

The ICMR released a subsequent statement last Saturday to argue that the letter was aimed at cutting unnecessary red tape without bypassing any necessary process.

But controversy re-emerged the day after, when a release from the Ministry of Science and Technology was edited to remove mention of a timeframe for the development of an Indian vaccine, including a reference that no vaccine against the coronavirus could be ready before next year.

Dr Chandrashekhar Gillurkar, director of the Nagpur-based Gillurkar Multispeciality Hospital that is one of the sites chosen for the Covaxin trial, said: "The full trial is something that will take time and should not be unduly hurried.

"We should follow the process laid out in the trial protocol, keeping in mind its safety procedures."