Photo/Illutration Medical workers in protective clothing treat a COVID-19 patient at the intensive care unit in the public Oceanico hospital, in Niteroi, Brazil, on Dec. 11. (AP Photo)

SAO PAULO--Brazil’s health regulator Anvisa said on Monday that China’s health authorities are not transparent in authorizing emergency use of COVID-19 vaccines, a statement that may further inflame political tension in the South American country.

Brazilian President Jair Bolsonaro, a consistent critic of China, has repeatedly cast doubt on the CoronaVac vaccine being developed by China’s Sinovac Biotech Ltd., saying its “origin” made it untrustworthy.

Meanwhile, in Sao Paulo, Brazil’s most populous state, authorities have made a hard bet on the vaccine, with Governor Joao Doria, a Bolsonaro enemy, saying the state expected to start vaccinating its residents in January.

Sao Paulo will not be able to begin using the Sinovac vaccine until it is approved by Anvisa, however. While the health regulator has long been largely apolitical, Bolsonaro has been appointing allies to it in recent months, stoking fears among health professionals that its decisions may be affected by political considerations.

“Brazil is the international leader in the evaluation process for CoronaVac,” Anvisa said in a statement on its website.

“The vaccine has had an emergency use authorization in China since June of this year. The Chinese criteria for granting emergency use authorization are not transparent, and there is no available information about the criteria currently in use by Chinese authorities to make these decisions.”

At least tens of thousands of people have taken the Sinovac vaccine in China’s emergency use program, officially launched in July, that targets limited groups of high-risk people. Two candidates developed by units of state-backed Sinopharm are included in the program.

China has not made public details of how it determines whether a novel coronavirus vaccine is qualified for emergency use. Its National Health Commission did not respond to a request for comment.

A Sinovac representative declined to comment but referred to a news conference in October at which a health official said the emergency inoculation was launched after stringent reviews and was in accordance with China’s laws and World Health Organization’s rules.

These vaccines showed “very good safety and immunogenicity readings in Phase 1 and Phase 2 clinical trials,” the official said.

CoronaVac is undergoing Phase 3 testing in Sao Paulo.

Doria said earlier on Monday that efficacy data would be released on Dec. 23, eight days later than initially planned, to allow for a larger sample size and more complete analysis.