Brazil's federal health regulator Anvisa has suspended the use of over 12 million doses of a Covid-19 vaccine developed by China's Sinovac Biotech Ltd that were produced in an unauthorised plant, it said in a statement.

Anvisa said it was alerted on Friday by Sao Paulo's Butantan Institute, a biomedical centre that has partnered with Sinovac to locally fill and finish the vaccines, that 25 batches, or 12.1m doses, sent to Brazil had been made in the plant, according to a Reuters report.

“The manufacturing unit ... was not inspected and was not approved by Anvisa in the authorisation of emergency use of the mentioned vaccine,” the regulator said. The ban was “a precautionary measure to avoid exposing the population to possible imminent risk,” it added.