In Conversation Health

Coronavirus | I would not take the vaccine without efficacy data: Gagandeep Kang

Gagandeep Kang at CMC Hospital, Vellore.   | Photo Credit: C. Venkatachalapathy

A year after the outbreak of the novel coronavirus, which has claimed 1.8 million lives so far, scientists, manufacturers and drug regulators the world over have been speeding up the timelines for the development, testing and approval of vaccines for emergency use. Three safe and efficacious vaccines from Pfizer, Moderna and AstraZeneca have already been greenlighted.

In India, the Hyderabad-based Bharat Biotech has been working feverishly to develop and test a COVID-19 vaccine, Covaxin, that uses a time-tested inactivated vaccine platform; but the haste shown by the Indian drug regulator to approve it in the absence of efficacy data has taken the shine off an indigenously developed lifesaver. We speak to Gagandeep Kang, Professor of Microbiology at Christian Medical College, Vellore, who has extensive experience in vaccine research, about the rush to grant approval for the vaccine without efficacy data.

“Bharat Biotech has data from animal challenge studies that are supportive of efficacy, but that is not an automatic bridge to human efficacy,” says Dr. Kang. From humans, Bharat Biotech must be following up their Phase I and Phase II participants for safety and immunogenicity, and may have some data, but that is not going to be sufficient, she says. The company really will need efficacy data from its Phase-III trial and is in the process of recruitment, vaccination and data collection. But that interim data, crucial for an approval, will still take a few weeks or months to come.

The approval granted to Bharat Biotech’s Covaxin flies in the face of the regulator’s own guidance to vaccine manufacturers. The September 2020 guidance explicitly mentions that 50% efficacy would be considered acceptable for emergency use approval. But it appears that our expert committee has followed a path similar to the Russian and Chinese regulators in not requiring human efficacy data for approval, says Dr. Kang.

During the second phase of human clinical trials of Covaxin at SRM Hospital in Tamil Nadu.

During the second phase of human clinical trials of Covaxin at SRM Hospital in Tamil Nadu.   | Photo Credit: B. Velankanni Raj

More sense to wait

The urgency to approve the vaccine even in the absence of efficacy data would have been permissible if COVID-19 had been life-threatening with a very high likelihood of death in those who are infected, as in the case of Ebola and Nipah. “For a disease with a low mortality rate and a population-wide vaccination strategy, it makes more sense to wait and have an efficacious vaccine instead of wide use of a vaccine that might not work,” she says.

While granting permission, the regulator had said the vaccine will be used in a ‘clinical trial mode’, a phrase never before used in any vaccine approval. “I really do not know what ‘clinical trial mode’ after approval means,” says Dr. Kang. “I am not sure what is planned for consent post-introduction and I am not clear about whether these studies and medical expenses in case of serious adverse events will be the responsibility of the company or the government. If it is the company, it is not clear to me how expanding their studies from thousands to lakhs or millions with the increased requirements benefits the company in its goal to full licensure.”

The assertion that Covaxin will be effective against mutant strains even in the absence of efficacy data is based on the premise that using the whole virus that is inactivated might provide increased protection. So if Covaxin is based on an old viral strain, will it continue to work? We will just have to wait for data from humans and from the laboratory to know that, says Kang.

With Prime Minister Modi emphasising atmanirbharta (self-reliance) one wonders if that is what prompted the regulator to approve the vaccine even in the absence of any supporting efficacy data. “Covaxin, Covishield and many other vaccines are made in India, and we should be proud of our vaccine companies. But if the question is — did Indian science make the vaccine candidate and did Indian companies develop it, then the answer to the first part is variable and to the second is always yes,” says Dr. Kang. “Covaxin is based on an Indian strain and a proven technology that Bharat Biotech has used for many vaccines, but has a new adjuvant that was developed in the U.S. Covishield’s viral vector construct was developed by the University of Oxford and then transferred by AstraZeneca to India. So, both are examples of atmanirbharta but have an element of non-Indian science — and to me that is fine.”

Vials of Covishield at the Serum Institute of India, Pune.

Vials of Covishield at the Serum Institute of India, Pune.   | Photo Credit: Reuters

Vaccine hesitancy

“There is a real danger that the non-transparent manner in which the approval was granted to Covaxin even without efficacy data might lead to increased vaccine hesitancy. Even without missteps we have misinformation, and any grounds for concern will be blown up into much larger conspiracy theories,” warns Dr. Kang. “We are not yet as badly affected with vaccine hesitancy as the West, but we do have a growing problem. We ignore this at our own peril. Decreased trust in vaccines can lead to an inability to achieve our public health goals of reducing mortality and preventing spread.”

Given that the inactivated vaccine platform is time-tested and Bharat Biotech has developed many vaccines using this platform, animal studies show promise and the vaccine appears to be safe, will Dr. Kang be willing to take Covaxin even in the absence of efficacy data? “I have no problem with volunteering for the Covaxin trial, because I think it is potentially a good vaccine, but unfortunately CMC Vellore is not a centre. I would go through the process as a volunteer and could get a vaccine or placebo and I am fine with that because I would be contributing to the generation of scientific data that would inform vaccine development,” says Dr. Kang. “But if the vaccine were to be offered to me under conditions of ‘restricted use’, as a matter of ‘abundant caution’, in ‘clinical trial mode’, I would not take the vaccine without efficacy data, because it makes no sense to me. Once clinical efficacy data are available and have been reviewed by the regulator, [I have] no issues at all with taking the vaccine.”

Related Topics
This article is closed for comments.
Please Email the Editor

Printable version | Mar 7, 2021 8:19:24 AM | https://www.thehindu.com/sci-tech/health/i-would-not-take-the-vaccine-without-efficacy-data-gagandeep-kang/article33527186.ece

Next Story