Health officials in Brazil said on Tuesday that a vaccine produced in China for COVID-19 is slightly more than 50 percent effective in preventing infections, above the World Health Organization (WHO) benchmark standards for vaccine effectiveness, but well below several vaccines produced by Western countries.
The New York Times reported that the Butantan Institute in São Paulo has released findings indicating that Sinovac’s CoronaVac injection was far less effective than competing candidates produced by the Moderna, Pfizer and AstraZeneca companies.
The actual effectiveness rate is also much lower than the rate officials had previously estimated for the Sinovac candidate; Last week, it was reported that officials in São Paulo had estimated the CoronaVac to be 78 percent effective in preventing COVID-19.
The difference appears to be in the data set, as the figures released last week did not take into account patients who had experienced “very mild” coronavirus infections after receiving the injection.
Overall, the CoronaVac remains 100 percent effective in preventing “severe” or “moderate” coronavirus infections, the Butantan Institute has found, while mild or very mild infections remain possible after receiving the injection.
The lower effectiveness of the Sinovac candidate could lead to a lower demand for Chinese public health experts; The Chinese government has sought to forge closer ties with countries around the world through its vaccine distribution program.
China has been pursuing an accelerated roll-out of its vaccine in recent weeks and has announced that it plans to vaccinate 50 million people within its borders by January 15, allowing many to receive a second injection before the start of the Chinese New Year celebration.
A second vaccine candidate, produced in China by Sinopharm, was rated by health officials in the United Arab Emirates as 86 percent effective in preventing COVID-19 infections.