Even as two potential vaccines for COVID-19 have emerged in India, scientists said it was imperative to strike a balance between giving it high priority and rushing into a process that takes months and even years. The note of caution from scientists comes just a day after the ICMR announced that its vaccine candidate Covaxis will be launched by August 15. Ahmedabad-based Zydus Cadila also announced that it has got the Drugs Controller General of India's (DCGI) nod for human trials for its candidate ZyCoV-D.
“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. He said 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.
Virologigist Upasana Ray said that an accelerated launch or promise for launch of a vaccine against the 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 scientists at CSIR-IICB, Kolkata, told PTI.
The ICMR had yesterday said 12 clinical trial sites for Covacin, 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.
Some scientists questioned the timeline of the announcement, and advised against subverting the due vaccine development process.
Immunologist Satyajit Rath said the ICMR letter is 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.
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.
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.
Ray noted that there are some broad mandatory steps for developing a vaccine. Preclinical tests in small animals and mammals, she stressed, are essential to assess neutralising antibody titers and that itself can take at least a month or two.
(With PTI inputs)