BEIJING (AP) – In a rare admission of the weakness of Chinese coronavirus vaccines, the country’s top disease control official says their effectiveness is low and the government is considering mixing them up for a boost.
Chinese vaccines “don’t have very high protection rates,” said director of the Chinese Centers for Disease Control Gao Fu at a conference Saturday in southwestern Chengdu.
Beijing has distributed hundreds of millions of doses overseas in an attempt to cast doubt on the effectiveness of the Pfizer BioNTech vaccine, made using the previously experimental messenger RNA or mRNA process.
“We are now formally considering whether we should use different vaccines from different lines of technology for the immunization process,” said Gao.
Officials at a press conference on Sunday did not directly respond to questions about Gao’s comment or possible changes in official plans. However, another CDC official said developers are working on mRNA-based vaccines.
Gao didn’t answer a call for further comment.
“The mRNA vaccines developed in our country have also entered the clinical trial phase,” said Wang Huaqing, official. He did not give a schedule for possible use.
Experts say mixing vaccines or sequential immunization could increase their effectiveness. Researchers in the UK are investigating a possible combination of Pfizer-BioNTech and the traditional AstraZeneca vaccine.
The coronavirus pandemic, which began in central China in late 2019, marks the first time the Chinese pharmaceutical industry has played a role in responding to a global health emergency.
Vaccines from Sinovac, a privately held company, and Sinopharm, a state-owned company, make up the bulk of China’s vaccines, which are sold in several dozen countries, including Mexico, Turkey, Indonesia, Hungary, Brazil, and Turkey.
The effectiveness of a Sinovac vaccine in preventing symptomatic infections has been found by researchers in Brazil to be only 50.4%, close to the 50% threshold at which health experts believe a vaccine is useful. By comparison, the Pfizer BioNTech vaccine was found to be 97% effective.
Health experts say Chinese vaccines are unlikely to be sold to the US, Western Europe and Japan due to the complexity of the approval process.
A Sinovac spokesperson, Liu Peicheng, admitted varying levels of effectiveness were noted, but said it could be due to the age of the people in a study, the strain of the virus, and other factors.
Beijing has not yet approved foreign vaccines for use in China.
Gao did not provide details on possible changes in strategy, but did cite mRNA as a possibility.
“Everyone should consider the benefits mRNA vaccines can bring to humankind,” said Gao. “We have to follow it carefully and not ignore it just because we already have several types of vaccines.”
Gao previously questioned the safety of mRNA vaccines. He was quoted by the official Xinhua News Agency as saying that he could not rule out negative side effects in December as they were being used in healthy people for the first time.
Chinese state media and popular health and science blogs have also questioned the safety and effectiveness of the Pfizer BioNTech vaccine.
As of April 2, around 34 million people in China had received both of the doses required for Chinese vaccines, and around 65 million had received one, according to Gao.
Sinovac spokesman Liu said studies have shown that protection “may be better” if the time between vaccinations is longer than the current 14 days, but gave no indication that this could be made standard practice.
Wu reported from Taipei.
This story has been corrected to show that Chinese vaccines have been donated or exported to several dozen countries, not 22, and that Sinovac is a private, not state-owned company.
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