Covaxin has an overall vaccine efficacy of 77.8 percent against symptomatic infections
Covaxin was among the first vaccines introduced in the country but there has been a delay in getting a clearance from the World Health Organization (WHO), resulting in Indians, who took the jab, missing out on travelling to many countries. Now, finally, WHO on Wednesday “granted Covaxin an Emergency Use Listing (EUL)”. The vaccine has been cleared for use across age groups (18+). The duration between two shots is of four weeks. The health body hasn't released any information related to vaccine's use on pregnant women and children.
What Is Covaxin?
It's an inactivated whole virus vaccine, containing SARS-CoV-2 particles that have been chemically deactivated. This means these particles can no longer infect cells but can stimulate immune response and make the vaccine suitable for people with compromised immune systems. It comes as a two-dose regimen, recommended to be taken 28 days apart.
Unlike mRNA vaccines, Covaxin does not require sub-zero temperatures for storage and can remain stable at 2-8 degrees Celsius. This makes it well-suited for low- and middle-income countries with warm climates and not enough cooling facilities.
Emergency Use Authorisation
When Covaxin got emergency authorisation by India's Central Drugs and Standards Committee (CDSCO), some had criticised it as the phase 2 clinical trials data was not published and phase 3 trials were still underway. But the regulator cited the need for protection against the Alpha variant, which was then spreading fast and outcompeting previous variants.
The Alpha variant was later overtaken by the more dangerous Delta variant. Covaxin manufacturer Bharat Biotech has repeatedly insisted that the vaccine is safe and provided a robust immune response.
The Phase 3 trial found that Covaxin had an efficacy of 93.4 percent against severe COVID-19 disease, and an overall vaccine efficacy of 77.8 percent against symptomatic infections. The vaccine also conferred more than 65 percent protection against symptomatic infection with the Delta variant, at least two weeks after the second dose, according to Gavi, the international vaccine alliance.
WHO Approval
The Technical Advisory Group (TAG), an independent advisory panel of WHO, had asked Bharat Biotech for additional clarifications. Last month, Dr Mariangela Simao, Assistant Director-General, Access to Medicines and Health Products at WHO, said Bharat Biotech has been submitting data regularly and quickly, but they submitted the last batch of data on October 18. WHO's approval was expected by October-end.
Previously, WHO officials had said that the organisation is in touch with Bharat Biotech daily in order to communicate all the additional clarifications required for the approval of Covaxin.
WHO Chief Scientist Soumya Swaminathan had said the TAG will meet on October 26 to consider the Emergency Use Listing for Covaxin. But even then the approval did not come. "The Technical Advisory Group for Emergency Use Listing expects the clarification from Bharat Biotech by end of this week and thus will reconvene for the final risk-benefit assessment on Wednesday, November 3," WHO had said.