The US drug regulatory authority has declined to grant emergency use authorisation (EUA) for Covaxin, India’s Covid-19 vaccine, for children aged between 2 and 18 years.

The vaccine’s developers have said they intend to continue pursuing its release in the US.

The US Food and Drug Administration (FDA) “at this time, has declined to issue an EUA for Covaxin in individuals 2 to 18 years of age”, the US-based bio-pharma company Ocugen, which had applied for the EUA, said in a media release on Friday.

Ocugen is developing Covaxin in the US and Canada after acquiring rights for the vaccine from the Hyderabad-based Bharat Biotech.

A researcher involved in the vaccine’s development said the FDA decision “has nothing do with the safety or effectiveness of the vaccine” but reflects a demand for additional clinical data from the US, which needs to be generated.

“Ocugen intends to continue working with FDA to evaluate the regulatory pathway for paediatric use of Covaxin,” the company said.

It added that the FDA decision would have no impact on a planned clinical trial to assess Covaxin in adults in the US.

In June 2021, Ocugen had withdrawn an EUA application for the use of Covaxin in adults on the recommendation of the FDA, which had asked the company to pursue an alternative regulatory pathway under which it would need to conduct clinical trials in the US.

The company had in November 2021 submitted an EUA request to the FDA for the paediatric use of Covaxin, but some regulatory affairs analysts had predicted the application would face challenges.

“The single-arm design of the paediatric immune-bridging study conducted solely in India and the lack of authorised use in adults (in the US) spell trouble for (Ocugen’s EUA) request for paediatric use,” Sue Sutter, a senior editor and regulatory affairs specialist, had written in Pharma Intelligence, a trade publication, in November 2021.

The FDA had in May 2021 revised its Covid-19 vaccine guidelines saying it “may decline to review or process EUA requests other than those for vaccines whose developers have engaged in an ongoing manner with the agency” during the vaccines’ development and clinical trials.

Covaxin was developed entirely in India, jointly by Bharat Biotech and the Indian Council of Medical Research, the government’s health research agency.

India’s drug regulatory authority approved Covaxin for adults in January 2021 and for children in October 2021 after an immuno-bridging study established the vaccine’s safety and its capacity to generate immune responses. But the country’s vaccination programme is currently not open to children aged below 15.