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Phase 3 efficacy data is missing, say experts, call for close monitoring

COVID-19 vaccine: Some independent scientists said that while data from the vaccine’s Phase 1 and Phase 2 trials is very encouraging, they questioned the process of approval when efficacy data from the vaccine’s Phase 3 trials, which began in November, hadn’t come in.

Written by Amitabh Sinha , Prabha Raghavan | New Delhi, Pune |
Updated: January 4, 2021 8:01:16 am
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Members of the National Covid-19 task force clarified that Covaxin, the vaccine being developed by Bharat Biotech, would be used in a “clinical trial” mode and Union Health Minister Harsh Vardhan said its emergency use approval was “a strategic decision for our vaccine security.”

But some independent scientists said that while data from the vaccine’s Phase 1 and Phase 2 trials is very encouraging, they questioned the process of approval when efficacy data from the vaccine’s Phase 3 trials, which began in November, hadn’t come in. Efficacy data is an indication of how effective the vaccine is in preventing the virus attack.

“If you take a look at what was proposed by the DCGI (Drug Controller General of India) as an adequate data package back in September, when they published their draft guidance (for approval of Covid-19 vaccines), it was very clear that they wanted safety and efficacy data and it was expected that, for the safety data, there would be at least two months of follow up,” said vaccine scientist and Christian Medical College professor Dr Gagandeep Kang.

“In the case of Covaxin…you haven’t finished enrolment. So, where is your safety data based on what DCGI asked for? Obviously, there’s no efficacy data either,” she said.

Said Shahid Jameel, a virologist and director of Trivedi School of Biosciences at Ashoka University: “Even emergency use authorisation requires efficacy data… These Indian vaccines would eventually go into the international market as well. It is very important that there is trust in our regulatory institutions. Otherwise, these same companies would suffer.”

Randeep Guleria, director of AIIMS and member of the National Covid-19 task force, told The Indian Express that the approval to Covaxin was given to ensure that in case there was a sudden surge in cases, and the availability of Oxford University vaccine was insufficient, it could be deployed “in clinical trial mode”.

Jameel said this was all the more reason why the approval for Covaxin need not have been rushed through.

“The Serum Institute has already said that it is ready with at least 50 million doses. And the Bharat Biotech vaccine is not being deployed immediately. So the proper thing would have been to wait for the preliminary data from the phase-III trials to come in, and then grant the approval. The trials are already on, and the preliminary data would be available within a few weeks,” he said.

Satyajit Rath, an immunologist who was formerly with the National Institute of Immunology in New Delhi, said scientists were not questioning the safety or effectiveness of the vaccine itself but raising concerns about the institutional process.

“The problem is not in the form of any enhanced risk to the individual who is taking the vaccine. The problem is at the policy level, at the regulatory level. There are several issues with the way the approval has been granted, which can lead to people losing confidence in the regulatory system,” he said.

L Shashidhara, a biologist and professor at IISER, Pune suggested a way forward that was in agreement with what Guleria described.

“Use of Covaxin and other vaccines for which data on efficacy is limited should be treated as extended clinical trials. While they are being produced in large quantities and subjected to batch testing, the government should build capabilities across the country to monitor immune response to different vaccines and assess the efficacy across populations. This helps in better strategizing the vaccination programme prior to larger scale implementation,” he said.

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