Brazil's decision to halt trials of a Chinese-developed Covid-19 vaccine triggered a politically charged row Tuesday as health officials expressed "indignation" over the move and far-right President Jair Bolsonaro claimed it as a victory.
Brazilian health regulator Anvisa announced late Monday it was suspending clinical trials of CoronaVac, developed by Chinese pharmaceutical firm Sinovac Biotech, after a "severe adverse incident" involving a volunteer in the study.
Privacy regulations prevent officials from disclosing details on the incident, which came as a setback for one of the most promising vaccines aiming to end the pandemic.
However Brazilian media reports said the fatality was a suicide, citing a leaked death certificate.
Both Sinovac and the public health institute coordinating the study in Brazil said the incident had nothing to do with the vaccine.
"There is no relation with the vaccine," said Dimas Covas, head of the Butantan Institute, the respected public health center coordinating the study in Brazil.
"We can't go into details because of privacy regulations, but what I can tell you is that Anvisa has all the data, all the information in its hands, and the conclusion from the (independent expert) report is exactly that: There is no link with the vaccine," he told a news conference.
Anvisa's decision, he said, "came as a surprise… and caused indignation here at Butantan."
Bolsonaro, who has railed against CoronaVac as the vaccine from "that other country" and blocked the federal government from purchasing it, meanwhile said he considered the regulatory decision "another win for Jair Bolsonaro."
CoronaVac has been caught up in a messy political battle in Brazil, where its most visible backer has been Sao Paulo Governor Joao Doria, a leading Bolsonaro opponent.
Sao Paulo state has a deal with Sinovac to buy a total of 46 million doses — six million produced in China and the rest produced in Sao Paulo, which broke ground last week on a factory to make the vaccine domestically.
Bolsonaro has thrown his support behind another vaccine, developed by Oxford University in Britain and the pharmaceutical firm AstraZeneca.
Bolsonaro faces criticism from experts for his handling of the pandemic, which has included playing down the virus, opposing lockdown measures and relentlessly promoting the drug hydroxychloroquine despite studies showing it is ineffective against Covid-19.