Brazil halts trials of Chinese-made virus vaccine

Medical authorities in Brazil on Tuesday defended their decision to halt halted clinical trials of the potential coronavirus vaccine CoronaVac, and denied it was politically motivated.

Antonio Barra Torres, the head of Brazil's national health surveillance agency, Anvisa, said it was the only decision possible until further information was received.

Critics  of President Jair Bolsonaro said they feared the move was motivated not by science but by the leader's political hostility to the country and to the state involved in producing the vaccine candidate.

The potential vaccine is being developed by Chinese biopharmaceutical firm Sinovac and in Brazil would be mostly produced by Sao Paulo's state-run Butantan Institute.

About 10,000 volunteers are taking part in phase three tests in one of the nations hardest hit by COVID-19.

Sao Paulo state health authorities said at a press conference Tuesday that Anvisa sent a single email at 8:40 p.m. saying the tests should be stopped. They also said the incident with one of the trial volunteers was not related to the tests.

Anvisa did not describe the Oct. 29 event that prompted the halt.

Torres, a close ally of Bolsonaro's, said the trials would only go ahead after the agency rules on an independent international report of the case. He says he does not have enough information on what happened for now.

Sinovac issued a short statement in China on Tuesday saying it was in touch with Brazilian authorities and insisted, "The clinical study in Brazil is strictly carried out in accordance with GCP requirements and we are confident in the safety of the vaccine," referring to Good Clinical Practice, a set of international standards for ethics and data quality in clinical research.

Temporary halts of drug and vaccine testing are relatively common. In research involving thousands of participants, some are likely to fall ill.

Saõ Paulo health authorities said they had a meeting with Anvisa leaders earlier on Tuesday, but received no feedback on when the tests will be allowed to continue.

The CoronaVac shot has already stirred controversy in Brazil, where President Bolsonaro has cast doubt on its prospective effectiveness.

He publicly rejected it last month, saying Brazilians would not be used as guinea pigs. The declaration followed news that his health minister, Eduardo Pazuello, had agreed to purchase CoronaVac doses produced locally by Butantan.

Bolsonaro has often expressed mistrust of China, particularly on the campaign trail in 2018, although he has softened his rhetoric somewhat in office. And the governor of the state producing the vaccine, Sao Paulo's. João Doria, is a political rival and an outspoken critic of the president's pandemic response.

CoronaVac is being tested in seven Brazilian states, plus the federal district where the capital Brasilia lies.

Following the imbroglio last month surrounding the CoronaVac shot, Anvisa authorized the import from China of 6 million doses. The potential vaccine cannot be administered to Brazilians as it isn't yet approved locally, the agency said at the time.