The lukewarm results could also be problematic for Chinese officials, given they had touted the effectiveness of vaccines made by Sinovac and Sinopharm. Even though the vaccines had not received regulatory approval and data from advanced trials had not been made public, Beijing gave them to thousands of Chinese as part of an emergency use policy ; it plans to vaccinate 50 million people by the middle of next month.
Chinese state media played down the news from Brazil. Global Times, a state-owned nationalist tabloid, ran a headline saying Sinovac vaccine was “100% effective in preventing severe cases, could reduce hospitalizations by 80%.”
The new data could increase skepticism among people around the world who are already wary of Chinese-made vaccines, given the country has a history of vaccine quality scandals. A study by the Chinese University of Hong Kong found that only 37.2% of people polled in Hong Kong were willing to be vaccinated.
Scientists had previously raised questions about how piecemeal the efficacy data for Chinese vaccines had been published. Indonesia said on Monday that its interim analysis found CoronaVac to have an efficiency rate of 65.3%. Turkey last month said it had an efficacy rate of 91.25%, but that was based on preliminary results from a small clinical trial.
The vaccine has long taken on a political dimension in Brazil. President Jair Bolsonaro had spoken derisively about CoronaVac, fueling a growing anti-vaccination movement in the country, where more than 200,000 people have died from Covid-19. The vaccine was defended by the governor of São Paulo, João Doria, who is expected to run for president in 2022 and who is among the most vocal critics of Mr. Bolsonaro.
In Brazil, officials say the previously reported higher efficacy rate for CoronaVac was linked to the protection it offered against the development of symptoms of Covid-19 severe enough to require treatment. While officials claimed last week that the vaccine offered absolute protection against moderate to severe symptoms, they had not disclosed another group who had “very mild” infections despite being vaccinated.
Denise Garrett, Brazilian-American epidemiologist and vaccine expert, said there was no reason to doubt the safety of CoronaVac, adding that the data presented so far suggested that it would provide a satisfactory level of protection. . But Dr Garrett said the vague and sometimes misleading way in which information about the vaccine has been made public could undermine people’s confidence in its reliability and fuel the political battle over the vaccine.