The lukewarm results could also be problematic for Chinese officials, as they consider the effectiveness of the vaccines made by Sinovac and Sinopharm. Although the vaccines were not approved by the regulations, and data from late stages of trials were not released, Beijing gave them to thousands of Chinese people under an emergency use policy; it plans to vaccinate 50 million people by next month.
State media in China have downplayed the news from Brazil. Global Times, a state-run nationalist pony newspaper, posted a headline saying the Sinovac vaccine was “100 percent effective in preventing serious cases, which could reduce hospitalizations by 80 percent.”
The new data could increase skepticism among people around the world who are already wary of Chinese-made vaccines, as the country has a history of vaccine quality scandals. A study by the Chinese University of Hong Kong found that only 37.2 percent of respondents in Hong Kong were willing to be vaccinated.
Scientists have already raised questions about the way in which efficacy data on Chinese vaccines have been released. Indonesia said on Monday that CoronaVac had an efficiency rate of 65.3 percent in the interim analysis. Last month, Turkey said it had an efficiency rate of 91.25 percent, but it was based on preliminary results from a small clinical trial.
The vaccine has long had a political dimension in Brazil. President Jair Bolsonaro spoke ridiculously about CoronaVac, which fueled a growing anti-vaccination movement in the country, where more than 200,000 people died from Covid-19. The vaccine was put forward by São Paulo governor João Doria, who is expected to be elected president in 2022 and is among Bolsonaro’s most outspoken critics.
In Brazil, officials say the higher efficacy rate announced by CoronaVac earlier relates to the protection it provided against the development of Covid-19 symptoms that were significant enough to require treatment. While officials claimed last week that the vaccine provided absolute protection against moderate to severe symptoms, they did not disclose another group that had “very mild” infections, despite the vaccination.
Denise Garrett, a Brazilian-American epidemiologist and vaccine expert, said there was no reason to doubt the safety of CoronaVac, adding that the data so far had suggested it would provide a satisfactory level of protection. But dr. Garrett said the vague and sometimes misleading way in which information about the vaccine was disclosed could scare people’s confidence in its reliability and fuel the political battle over the vaccine.