Brasilia [Brazil], January 13 (ANI): The Chinese Sinovac vaccine has been found to be far less effective than vaccines developed by Pfizer-BioNTech and Moderna, according to a Brazil government statement on Tuesday, which raised questions about the lack of transparency of Chinese-made vaccines.

The efficacy of the Chinese-made vaccine was 50.38 per cent in Brazil's late-stage trials.

While the number exceeds the threshold required for regulatory approval, it falls far below the 78 per cent previously announced, raising questions as to the veracity of the data and fueling skepticism over the apparent lack of transparency regarding Chinese vaccines, CNN reported.

The Butantan Institute, which has been conducting the trials in Brazil, announced that the vaccine had a 78 per cent efficacy against mild to serve COVID-19 cases.

"The Butantan Institute and the Government of Sao Paulo reported that the coronavirus vaccine achieved a 50.38 per cent overall efficacy rate in the clinical study conducted in Brazil, in addition to (an efficacy rate of) 78 per cent for mild cases and 100 per cent for moderate and severe cases of Covid-19. All rates are higher than the 50 per cent level required by the WHO (World Health Organization)," according to a statement published by the government of Sao Paulo.

The Sinovac vaccine is also less effective than its domestic Chinese competitor, developed by the state-owned Sinopharm, which it says is 79.34 per cent effective, CNN reported.

"Regarding the overall efficacy of the analysis, we met the requirements of the WHO with 50.38 per cent," CNN quoted Ricardo Palacios, medical director for clinical research at the Butantan biomedical center in Sao Paulo as saying.

Yanzhong Huang, a senior fellow for global health at the US-based Council on Foreign Relations, described the 50.38 per cent efficacy of the Sinovac vaccine as a "disappointing" result.

Russia's Sputnik V vaccine is 91 per cent effective, while the United Kingdom's vaccine, developed by Oxford University and AstraZeneca, has an average efficacy of 70 per cent.

According to CNN, the Chinese Sinovac vaccine has signed deals to provide 46 million doses of its Covid-19 vaccine to Brazil. (ANI)