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 acknowledgment of the weakness of Chinese vaccines.
Chinese medicines “do not have very high rates of protection,” Gao Fu, director of the Chinese Centers for Disease Control, said at a conference Saturday in the southwestern city of Chengdu.
Beijing has distributed hundreds of millions of doses in other countries, trying to cast doubt on 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,” said Gao.
Beijing has not yet approved foreign vaccines for use in China.
Gao did not discuss possible changes to the strategy, but did mention messenger RNA, a previously experimental technology used by Western vaccine manufacturers, while Chinese pharmaceutical companies used established techniques.
“Everyone should consider the benefits messenger RNA vaccines can have for mankind,” he said. “We have to monitor it carefully and not ignore it just 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 a statement from him in December saying it could not rule out negative side effects because it was the first time the vaccines had been used in healthy people.
Officials holding a press conference on Sunday did not immediately respond to questions about Gao’s comments or possible changes to official plans. But another member of the Center for Disease Control noted that messenger RNA vaccines were in the works.
“Messenger RNA vaccines developed in our country have also entered the clinical trial phase,” said the official, Wang Huaqing, who did not specify deadlines for their potential distribution.
Chinese state media and popular science and health blogs have also questioned the safety and effectiveness of the Pfizer’s vaccine, which uses messenger RNA.
By April 2, about 34 million people had received the required two doses of Chinese vaccines, while about 65 million people had already received one dose, Gao said.
Experts note that mixing vaccines or sequential immunization can increase effectiveness. Several trials in different parts of the world are examining the effect of mixing vaccines or administering a booster dose after a long period of time. Researchers in Great Britain are studying a possible combination of the vaccines Pfizer and AstraZeneca.
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.
The 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 State Department.
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.
According to health experts, Chinese vaccines are unlikely to be sold to the United States, Western Europe and Japan due to the complexity of the regulatory approval process.