SÃO PAULO—Brazil’s health regulator Anvisa said Monday it has suspended clinical trials of China’s Sinovac coronavirus vaccine, long expected to be one of the first to be approved in the country, following a “severe adverse event.”
Anvisa said in a statement late Monday that the event occurred on Oct. 29, without giving further information, or an explanation of why it took more than a week to communicate the problem.
Brazil’s Butantan Institute, the research center in São Paulo that has been developing the vaccine in partnership with Sinovac, a private Chinese company, said Monday that it was surprised by Anvisa’s decision. It said it was investigating, and would hold a press conference Tuesday morning.
Brazilian local press reported that the director of the Institute said one volunteer had died but the death was unrelated to the vaccine trials and didn’t warrant the suspension. The institute didn’t respond to a request for comment on the press reports.
The Chinese vaccine has been at the center of a political battle in Brazil between President Jair Bolsonaro and São Paulo’s powerful state governor João Doria. Mr. Doria, who is expected to run against Mr. Bolsonaro in Brazil’s 2022 presidential elections, has spearheaded the development in Brazil of the Sinovac vaccine. He has said he hopes to vaccinate everyone in São Paulo state as early as March next year.
Brazil has been one of the countries hardest hit by the pandemic so far, registering more than 160,000 deaths, second only to the U.S.
Earlier Monday, Mr. Doria said that the state has also begun construction of a facility to produce the vaccine locally, which will be ready by September next year.
Meanwhile, Mr. Bolsonaro has backed a rival Covid-19 vaccine being developed by the University of Oxford and AstraZeneca, issuing a decree in August to set aside more than $350 million to purchase 100 million doses. The federal government has said it hopes to start administering that vaccine in April, after clinical trials were temporarily put on hold in September when one participant fell ill.