“The protection rates of existing vaccines are not high,” Gao Fu, director of the Chinese Center for Disease Control and Prevention, told a conference in the southwestern city of Chengdu on Saturday.
He listed two options to solve the problem: one is to increase the number of doses, or adjust the dosage or interval between shots; the other is to mix vaccines developed from different technologies.
China has positioned itself as a leader in Covid-19 vaccine development and distribution, promoting and supplying its vaccines to countries all over the globe, including Indonesia, Zimbabwe, Turkey and Brazil.
“More than 60 countries have approved the use of Chinese vaccine. The safety and efficacy of Chinese vaccine is being widely recognized by various countries,” Chinese Foreign Minister Wang Yi said at a news conference in March.
The relatively low efficacy rate of Chinese vaccines, however, could hamper credibility and dent Beijing’s so-called vaccine diplomacy.
The two pharmaceutical firms that supply the majority of Chinese Covid-19 vaccines to the world have not published comprehensive clinical trial data in medical journals on their vaccines’ effectiveness. But from the interim results announced by the companies, their efficacy falls far behind the new type of vaccines developed in the West that use mRNA to trigger an immune response.
The CoronaVac vaccine developed by Sinovac, a private company, was found to have an efficacy rate of just 50.4% in clinical trials in Brazil. Another trial in Turkey showed it was 83.5% effective. State-owned Sinopharm said its two vaccines have efficacy rates of 79.4% and 72.5%.
In comparison, the Pfizer-BioNTech and Moderna vaccines have efficacy rates of 97% and 94%, respectively.
In that sense, Gao’s comments on the relatively low efficacy of Chinese vaccines were merely stating a well-known fact — but it was the first time a high-level official in China had publicly acknowledged it.
“What struck me most was that the suggestion of the relatively low efficacy rates of Chinese vaccines appears to be a deviation from what the Chinese state and social media has said. The official narrative portrays Chinese vaccines as both safe and effective,” said Yanzhong Huang, a senior fellow at the Council on Foreign Relations, who posted Gao’s speech on Twitter over the weekend.
As Gao’s comments gained traction on social media and made international headlines, Chinese censors quickly scrubbed discussions online, and state media swiftly put out an interview with Gao to walk back his comments.
“The protection rates of all vaccines in the world are sometimes high, and sometimes low. How to improve their efficacy is a question that needs to be considered by scientists around the world,” Gao was quoted as saying.
Huang, the expert on China’s public health, said the quick repudiation by the Global Times suggested Chinese authorities will not tolerate any challenge to their official narrative.
“Gao’s remarks were just an occasional aberration,” he said.
Additional reporting by Reuters.