An emergency like the current pandemic situation allows the drugs regulator to give restricted approval for vaccine which has been proven safe and immunogenic in phase II trials, said Indian Council of Medical Research Director-General Balram Bhargava on Tuesday.

Defending the drugs regulator’s decision to approve Bharat Biotech’s Covaxin for restricted use under clinical trials mode, Bhargava said consent would need to be taken from beneficiaries who are getting the vaccine and they need to be followed up.

“In a pandemic situation, restricted use is considered based on safety and immunogenicity data while the phase III is still on going. The immunogenicity data generated through the phase II clinical trials serve as surrogate data for efficacy. India’s Clinical Trials Rule 2019 provide for considering phase II results to guide the approval,” the ICMR chief said.

Vaccine trials

Talking about the Covishield trials in the UK, he said animal studies have clearly shown that the vaccine prevented pneumonia in monkeys while it exhibited immune response in mice. Similarly, the human trials also showed that the vaccine has a acceptable safety profile and good vaccine efficacy. In the studies carried out in 1,600 people in India, the vaccine was seen to be non-inferior to the UK vaccine, prompting the SEC (Subject Expert Committee of the Central Drugs Standard Control Organisation) and the drugs regulator to give it the approval.

Similarly, Bharat Biotech’s Covaxin, developed jointly with ICMR labs, showed excellent safety, immunogenicity and robust viral clearance, both in upper and lower respiratory tracts, in the animal studies. The phase I and II human trials showed there is very low adverse events and strong neutralising antibody response, very similar to human convalescent plasma. Even though the phase III efficacy trials are not over, the vaccine’s safety was clearly established in the 24,000 volunteers who received it, Bhargava said.

 

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