The United States Food and Drug Administration has rejected Bharat Biotech’s proposal for emergency use authorisation of its Covid vaccine, Mint reported on Friday. Ocugen, Bharat Biotech’s partner in the US, on Thursday said the company will now seek a full approval of Covaxin.

The US biopharmaceutical company said it will pursue the process of submitting a what for its coronavirus vaccine candidate. It is a request for permission to introduce a biologic product into interstate commerce, according to the US Food and Drug Administration.

“Although we were close to finalising our EUA application for submission, we received a recommendation from the FDA to pursue a BLA path,” said Shankar Musunuri, the chief executive officer and co-founder of Ocugen. “While this will extend our timelines, we are committed to bringing Covaxin to the US.”

Currently, many countries do not recognise Covaxin. Some of the countries that have approved Covaxin include Iran, Philippines, Mauritius, Mexico, Nepal, Guyana, Paraguay and Zimbabwe. As countries open their borders for non-essential travel to fully vaccinated individuals, a “vaccine passport” is fast becoming a travel requirement. A vaccine passport attests that its bearer is immune to a contagious disease.

The development comes at a time when Bharat Biotech is facing criticism for not sharing its phase-3 trial data nearly six months after its vaccine was granted an emergency use authorisation in India. In January, the company had said it would submit efficacy results by March.

However, on Wednesday, the firm said that the phase 3 trial data for Covaxin will be made public only in July. “Once data from final analysis of phase 3 studies are available, Bharat Biotech will apply for full licensure for Covaxin,” the company said.

Meanwhile, the Hyderabad company criticised a study that found that its vaccine produced significantly fewer antibodies than Covishield – the shot produced by AstraZeneca and Oxford University and manufactured by India’s Serum Institute.

“It is not a peer-reviewed publication, nor statistically and scientifically designed study, the study design and conduct reflect an ad hoc analysis, rather than predetermined hypothesis,” Bharat Biotech said. The company said that the study was not registered on the government’s Clinical Trial Registry and not approved by the Central Drugs Standard Control Organisation.

The study that Bharat Biotech objected to is a pre-print that concluded, based on observational data, that while both vaccines elicited good immune response after two doses, the amount of antibodies that was detected in recipients of Covishield was much higher than those who got Covaxin.

The study, first reported on June 6, showed that one dose of Covishield produced 10 times more antibodies than Covaxin. After a second dose was added, it was found that two shots of Covishield produced about six times more antibodies than Covaxin.

The study is yet to be peer reviewed but was shared on medRxiv, an online portal for unpublished reports on medical sciences. This is the first study that compares Covaxin and Covishield. However, many other scientists have pointed out what they claimed to be serious flaws in the study’s design.