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

A letter issued by the Indian Council of Medical Research (ICMR) on July 2 said an indigenously 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 when compared to the accelerated timeline international vaccine initiatives have adopted amid the coronavirus pandemic.

Some of the vaccine development efforts that began several months ago are currently 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 with Bharat Biotech International Limited (BBIL) to develop the vaccine under the name Covaxin.

A strain of the novel coronavirus is used, which was isolated by the National Institute of Virology, itself a part of ICMR's network. It is one of two indigenously developed vaccine candidates that are about to begin human trials.

Development of the other vaccine candidate has been done by Indian pharmaceutical company Zydus Cadila.

ICMR's July 2 letter was sent by its director-general, Dr 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 topmost level of the government".

"Kindly note that non-compliance will be viewed very seriously," the letter added.

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 July 5 statement.

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 standards of research must not be diluted in haste.

"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.

The deadline contravenes the time frame laid out in the trial protocol on the ICMR's clinical trials registry. According to it, 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.

"How do you reduce a 15-month time frame 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," Dr Jesani added.

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

The Aug 15 deadline has raised eyebrows also because it coincides with the date of India's independence, a day that is commemorated each year with an address from the country's prime minister during which he or she 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 it has the pandemic under control.

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

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

The ICMR released a subsequent statement on 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 statement from the Ministry of Science and Technology was edited to remove mention of a time frame for the development of an Indian vaccine, including a reference that no vaccine against the novel coronavirus could be ready before 2021.

Dr Chandrashekhar Gillurkar, director of the Nagpur-based Gillurkar Multispeciality Hospital that is one of the sites chosen for the Covaxin trial, told The Straits Times that ICMR's letter had worried him and that only initial conclusions of the vaccine's safety and efficacy can be drawn in around four weeks from the trial's commencement.

"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," he added.