ICMR said it aims to launch the world's first COVID-19 vaccine by August 15. (Representational)
India's COVID-19 vaccine programme has gained sudden traction but it is imperative to strike a balance between giving it high priority and rushing a process that usually takes months, even years, several scientists said on Saturday, a day after the ICMR announced it envisaged a preventive by next month.
There was hope but caution too as the Indian Council of Medical Research on Friday said it aims to launch the world's first COVID-19 vaccine by August 15.
The same day, Ahmedabad-based Zydus Cadila announced it has got the Drugs Controller General of India's (DCGI) nod for human clinical trials for a potential vaccine.
"Fast-tracking a vaccine trial in four weeks for safety, immunogenicity and efficacy is just not possible if things are to be done correctly," Shahid Jameel, virologist and CEO of the Wellcome Trust/DBT India Alliance, a public charity that invests in building biomedical sciences and health research framework, told PTI.
Immunogenicity is the ability of a foreign substance, such as an antigen, to provoke an immune response in the body of a human or other animal, he said.
Virologist Upasana Ray added that an accelerated launch or promise for launch of a vaccine against the novel coronavirus deserves applause but it is important to ask whether "we are rushing too much".
"We must rush albeit carefully. Giving this project high priority is absolutely important. However, excess pressure might not necessarily lead to a positive product for public use," the senior scientist at CSIR-IICB, Kolkata, told PTI.
India's premier medical body ICMR has said 12 clinical trial sites for the indigenous Covaxin, being developed in collaboration with the Hyderabad-based Bharat Biotech and the National Institute of Virology (NIV), have been identified.
It asked medical institutions and principal investigators to ensure that the subject enrolment is initiated no later than July 7.
"It is envisaged to launch the vaccine for public health use latest by August 15 after completion of all clinical trials," ICMR Director General Balram Bhargava said in his letter to the principal investigators of the 12 sites.
The tone of the letter had some scientists worried. They questioned the timeline of the announcement mentioned in the letter, and advised against subverting the due vaccine development process.
"The ICMR ''letter'' is, to say the least, a deeply inappropriate letter, in tone and content, both in terms of the integrity of due processes of product development, and in terms of technically realistic estimates," immunologist Satyajit Rath told PTI.
Vaccine development is a multi-phase process. Phase 1 trials are small-scale, usually involving few participants, to assess whether the vaccine is safe for humans.
Phase 2 trials often involve several hundred subjects, and mainly evaluate the efficacy.
The final phase involves thousands of people to further assess the efficacy of the vaccine over a defined period of time, and can last several months.
Ms Ray added that a vaccine normally takes at least 12-18 months to pass all necessary clinical trial phases.
"From now till August 15, the company has just over a months'' time to wrap up everything that normally a vaccine development process requires for releasing a vaccine for clinical use," she said.
"How can such a sharp timeline be even decided? Where does the evidence come from that by such a short time all the essential steps will be completed? What about the safety and efficacy, the fundamental steps of any drug development? Have even the pre-clinical studies been completed? Too much rush comes with possible risks," she said.
Ms Ray noted that there are some broad mandatory steps for developing a vaccine. Preclinical tests in small animals and mammals, she said, are essential to assess neutralising antibody titers and that itself can take at least a month or two.
A titer is a laboratory test that measures the presence and amount of antibodies in blood.
"Next, we check for safety. Then is the human trial. Even if we are in a deep rush we have to wait for some time for immunised individuals to start generating antibodies. After that a population needs to be monitored over time to investigate if people are still being infected," she explained.
Skipping steps could either be dangerous or lead to poor product, Ms Ray said.
"We must not compromise with the standard, the quality. We don't need to be the first to launch a drug but what we need is a Made in India vaccine that the entire world can rely on," she added.
The vaccine landscape in India has been also bolstered after the approval for Zydus Cadila's vaccine candidate. It was fast-tracked following a recommendation by the subject expert committee on COVID-19, considering the emergency and unmet medical need during the pandemic.