SAO PAULO (Reuters) - Brazil’s health regulator Anvisa said on Monday China’s health authorities are not transparent in their authorization of COVID-19 vaccines for emergency use, 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. Meanwhile, Sao Paulo Governor Joao Doria, a Bolsonaro enemy, said the state expected to start vaccinating its residents in January, though Brazil’s most populous state will not be able to use CoronaVac until it is approved by Anvisa. “Brazil is the international leader in the evaluation process for CoronaVac,” Anvisa said in a statement on its website on Monday. “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.” China’s foreign ministry spokesman Wang Wenbin said on Tuesday China had been attaching “great importance” to the safety and efficacy of its vaccines. While Brazil’s 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. At least tens of thousands of people have taken the Sinovac vaccine in China’s emergency use programme, officially launched in July, that targets limited groups of high-risk people. 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 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 at the time. 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. (This story corrects spelling of foreign ministry spokesman’s name in par 6.)