Health officials in Brazil said on Tuesday that a vaccine manufactured by China for COVID-19 is just over 50 percent effective at preventing infections, above the World Health Organization (WHO) standards for vaccine efficacy, but far below several vaccines produced by Western countries.
The New York Times reports that the Butantan Institute in São Paulo has released findings suggesting that the CoronaVac injection produced by Sinovac was far less effective than competing candidates manufactured by Moderna, Pfizer and AstraZeneca. .
The actual efficiency rate is also much lower than the officials previously estimated the Sinovac candidate; last week it was reported that officials in São Paolo estimated the CoronaVac to be 78 percent effective in preventing COVID-19.
The difference appears to be in terms of data collection, as the figures released last week did not count patients who experienced ‘very mild’ coronavirus infections after receiving the shot.
Overall, the CoronaVac remains 100 percent effective at preventing “severe” or “moderate” coronavirus infections, the Butantan Institute has found, while mild or very mild infections may remain after receiving the shot.
The lower efficiency rate of the Sinovac candidate could lead to a lower demand for China’s experts for public health outreach; The Chinese government has sought to forge closer ties with countries around the world through its vaccine distribution program.
China has been following a rapid explosion of its vaccine over the past few weeks, announcing before January 15 an attempt to vaccinate 50 million people within its borders so that a second shot can be fired at many people before the start of the country’s lunar new year celebrations.
A second vaccine candidate produced by Sinopharm in China is considered by health officials in the United Arab Emirates to be 86 percent effective in preventing COVID-19 infections.