Jab We Met

While the manufacturer of Covaxin got itself in a jam with Brazil following an inspection of its Hyderabad facility, AstraZeneca’s vaccine was put on hold in several nations after reports of blood clots. How safe are these vaccines?

- Dr KK Aggarwal

COVAXIN, India’s indigenous Covid-19 vaccine developed by Bharat Biotech in collaboration with the ICMR and National Institute of Virology, and AstraZeneca Covid-19 vaccine have come under the scanner for various reasons.

Earlier this month, Brazil’s health regulator rejected an application to give Covaxin a certificate of Good Manufacturing Practices following an inspection of Bharat Biotech’s site in Hydera bad recently. This move could potentially delay its ability to supply doses of the Covid-19 vaccine to the country until the issue is resolved. In the case of the Astra Zeneca vaccine, there were reports of blood clots that caused deaths in those who had taken it.

Incidentally, inactivated vaccines like Covaxin do not replicate and contain dead virus. Therefore, they are unlikely to revert and cause pathological effects. They are incapable of infecting people, but can still instruct the immune system to mount a defensive reaction against an infection.

But why develop an inactivated vaccine? Conventionally, inactivated vaccines have been around for decades. Numerous vaccines for diseases such as seasonal influenza, polio, pertussis, rabies, and Japanese encephalitis use the same technology to develop inactivated vaccines with a safe track record of over 300 million doses of supplies to date. It is a well-established, time-tested platform in the world of vaccine technology.