Questions raised by Brazil’s health regulator, ANVISA, could delay the acceptance of Covaxin in the South American country. ANVISA declined the Hyderabad-based manufacturer of the vaccine, Bharat Biotech, a “Certificate of Good Manufacturing” after an inspection of the firm’s production process in the first week of March revealed “non-conformities, implying a health risk for users”. An action plan submitted by Bharat Biotech on March 17 failed to assuage the regulator’s concerns. The company has clarified that “the requirements pointed out during the inspection will be fulfilled soon”. ANVISA’s unfavourable comments will, reportedly, not affect the Indian firm’s long-term partnership with the Brazilian pharma company Precisa Medicamentos to supply 20 million doses of Covaxin to the second-worst COVID-affected country. There are, however, compelling reasons to look at the issue beyond the vaccine supply agreement between the two countries.

Covaxin works by teaching the recipient’s immune system to manufacture antibodies against the novel corona virus. It does so by introducing an inactivated form of the virus that was isolated at the National Institute of Virology. The pathogen is drenched with a chemical, beta-propiolactone, to ensure that it does not replicate. According to ANVISA, Bharat Biotech has not validated the method of analysis to prove complete inactivation of the corona virus. It has called for more proof before certifying that live viruses are not present in the vaccine. The Hyderabad-based firm could not also convince Brazil’s regulator of its methods to obviate the presence of contaminating microorganisms in the injectible. In other words, ANVISA has flagged concerns related to sterility and purity — fundamental criteria in vaccine safety. The regulator, moreover, has raised questions over the vaccine’s potency.

All this should not be taken to indicate that Covaxin is unsafe. The vaccine has undergone rigorous clinical trials. In March, it registered a highly creditable efficacy score of more than 80 per cent. ANVISA’s concerns should, however, lead to conversations around regulatory interventions after clinical trials. “The concentration of impurities in the product may not be constant and may be different from the one evaluated during the clinical study,” the Brazilian regulator notes. Its queries frame two allied challenges for vaccine makers and regulators. One, given the compressed time spans that were forced upon the country’s medical bodies as a result of the pandemic, questions about safety and efficacy cannot be ruled out even after a vaccine has cleared due processes. Regulatory alacrity will be key to building trust in the vaccine. Two, transparency is non-negotiable when dealing with such issues. The concerns flagged by Brazil’s regulator acquire resonance in India as well. They must be promptly addressed.