The effectiveness of Chinese coronavirus vaccines is low and the government is considering combining them, the top authority of the Chinese disease control agency said on Sunday, in a rare official admission of the weakness of Chinese vaccines.
Chinese drugs “do not have very high protection rates,” Gao Fu, director of China’s Centers for Disease Control, told a conference in the southwestern city of Chengdu on Saturday.
Beijing has distributed hundreds of millions of doses to other countries and tried to raise doubts about the effectiveness of Western vaccines.
“It is now being officially considered whether we should use different vaccines from different technical lines for the immunization process,” Gao said.
Beijing has not yet approved any foreign vaccine for use in China.
Gao did not detail possible changes to the strategy, but mentioned messenger RNA, an experimental technology previously used by Western vaccine manufacturers, while Chinese pharmaceutical companies used established techniques.
“Everyone needs to consider the benefits that messenger RNA vaccines can bring to humanity,” he said. “We need to watch it carefully and not just ignore it because we already have different types of vaccines.”
Gao had questioned the safety of messenger RNA vaccines in the past. The official Xinhua news agency quoted him in a statement in December as saying it could not rule out adverse side effects because it was the first time the vaccines had been used in healthy people.
Officials holding a news conference on Sunday did not directly answer questions about Gao’s comments or possible changes to official plans. But another member of the Centers for Disease Control noted that messenger RNA vaccines were in the works.
“Messenger RNA vaccines developed in our country have also entered the phase of clinical trials,” said official Wang Huaqing, who did not give deadlines for their possible distribution.
Chinese state media and popular science and health blogs have questioned the safety and effectiveness of the Pfizer vaccine, which uses RNA messenger.
By April 2, about 34 million people had received the required two doses of Chinese vaccines, while about 65 million people had already received a dose, Gao said.
Experts note that mixing vaccines or sequential immunization can increase efficacy rates. Several studies in different parts of the world are studying the effect of mixing vaccines or administering a booster dose after a long period of time. Researchers in the UK are studying a possible combination of Pfizer and AstraZeneca vaccines.
The coronavirus pandemic, which began in central China in late 2019, marked the first time the Chinese pharmaceutical industry has played a role in responding to a global health emergency.
Vaccines manufactured by two state-owned pharmaceutical companies, Sinovac and Sinpopharm, have been exported to 22 countries, including Mexico, Turkey, Indonesia, Hungary, Brazil and Turkey, according to the foreign ministry.
Researchers in Brazil concluded that the effectiveness of a Sinovac vaccine in preventing symptomatic infections was only 50.4%, close to the 50% threshold at which experts consider a vaccine useful. In comparison, the Pfizer-BioNTech vaccine is 97% effective.
Health experts believe that Chinese vaccines are unlikely to be sold to the United States, Western Europe and Japan due to the complexity of the legal approval process.