The ICMR asked doctors in 12 hospitals to "fast track" clinical trials for the coronavirus vaccine.
The safety and interest of Indians is the topmost priority, the Indian Council of Medical Research (ICMR) said on Saturday after a memo from the agency triggered a backlash for setting August 15 as a target for developing a coronavirus vaccine, from both medical experts and the opposition.
A letter sent out earlier this week by the chief of India's top clinical research agency said it "envisaged" launching a novel coronavirus vaccine by Independence Day, prompting accusations by the opposition that the date was set to help Prime Minister Narendra Modi's government score political points.
The letter by ICMR Director-General Balram Bhargava that asked doctors in 12 hospitals to "fast track" clinical trials also stumped some doctors and researchers, who said it was unrealistic to set a six-week deadline for a candidate vaccine whose safety and efficacy trials have not even started.
Defending its message, the ICMR on Saturday said, "The letter by DG-ICMR to investigators of the clinical trial sites was meant to cut unnecessary red tape, without bypassing any necessary process, and speed up recruitment of participants."
"Just as red tape was not allowed to become a hindrance in the fast track approval of new indigenous testing kits or for introducing in the Indian market potential COVID-19 related drugs, the indigenous vaccine development process has also been sought to be insulated from slow file movement. The aim is to complete these phases at the earliest, so that population-based trials for efficacy could be initiated without delay," it said.
"ICMR's process is exactly in accordance with the globally accepted norms to fast-track the vaccine development for diseases of pandemic potential wherein human and animal trials can continue in parallel," the agency said.
The vaccine trials will be done following the best practices and rigour, and will be reviewed, as required, by a Data Safety Monitoring Board (DSMB), ICMR said.
"While issues raised in public domain from time-to-time by commentators are welcome, as they form an important part of feedback loop, the best of India's medical professionals and research scientists should not be second guessed for their professionalism or adherence to the highest scientific rigour. ICMR is committed to treat the safety and interest of people of India as a topmost priority," it added.
Dr Randeep Guleria, director of Delhi's All India Institute of Medical Sciences (AIIMS) told NDTV, "It is unrealistic and even the ICMR is aware of that. The letter was written to speed up processes."
Dozens of vaccine candidates are at various stages of development around the world to tackle the coronavirus pandemic. India, a leading manufacturer of vaccines and generic medicines, is expected to play a key role in this race.
At least seven vaccines are being researched in India and one, from Bharat Biotech and being developed with the ICMR, and another from drugmaker Zydus Cadila were approved for Phase I and Phase II clinical trials this week.
Phase I and Phase II trials typically test the safety of a drug before it enters Phase III trials that test its efficacy.
Each phase can last months, if not years, and although regulators globally have been fast-tracking trials on medicines and vaccines to treat the novel coronavirus, the timeline given out in the letter would be unprecedented.
"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," Anant Bhan, a doctor and public health researcher, said on Twitter.
"Even with accelerated timelines, this seems really rushed, and hence with potential risks, inadequate attention to process."
Several other health experts and political parties also questioned the launch date proposed in the letter, which was widely shared on social media.
Asserting that scientific advances cannot be "made to order", Communist Party of India (Marxist) general secretary Sitaram Yechury on Saturday alleged the ICMR was trying to rush the vaccine so that Prime Minister Narendra Modi could make the announcement on Independence Day.
Congress leader Prithviraj Chavan also alleged on Saturday that the ICMR's plans was aimed only at enabling the prime minister to make a big announcement from the Red Fort.