China-made coronavirus vaccines Sinovac and Sinopharm are low in effectiveness, Director Gao Fu of China Centers for Disease Control himself admitted at a conference in Chengdu, so the Chinese government plans to mix either with those made from the US and Europe to get better results for China citizens.

At a conference attended by foreign correspondents in Chengdu, the top Chinese health official made the rare admission, including the second batch of 25 million doses of Sinovac that arrived in Manila April 12.

President Duterte proudly received the first batch of one million doses in March, quickly followed by a donation of 500,000 doses.

Chinese vaccines “don’t have very high protection rates,” the head of China Centers for Disease Control was quoted as saying.

Beijing distributed hundreds of millions of doses abroad while trying to cast doubt on the effectiveness of the US-made Pfizer and Moderna vaccines.

“It’s now under formal consideration whether we should use different vaccines from different technical lines for the immunization process,” Gao said.

Officials at Chengdu news conference didn’t respond directly to questions about Gao’s comment or possible changes in official plans. But another CDC official said developers are working on Moderna or mRNA-based vaccines.

Informed of the official admission, Presidential spokesman Harry Roque nonetheless said China-made vaccines still provide protection against severe Covid-19 and deaths.

Reports show that China currently has five vaccines in use in its mass immunization campaign with an efficacy rate that ranges from just over 50 percent to 79 percent, based on what the companies have said.

In China, the other CCDC official, Wang Huaqing, revealed that Moderna vaccines were also being developed there, the effort having “entered the clinical trial stage.”

Experts say mixing vaccines, or sequential immunization, might boost effectiveness. Researchers in Britain are studying 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 drug industry has played a role in responding to a global health emergency.

Vaccines made by Sinovac, a private company, and Sinopharm, a state-owned firm, have made up the majority of Chinese vaccines distributed to several dozen countries including Mexico, Turkey, Indonesia, Hungary, Brazil, and Turkey.

The effectiveness of a Sinovac vaccine at preventing symptomatic infections was found to be as low as 50.4 percent by researchers in Brazil, near the 50 percent threshold at which health experts say a vaccine is useful. By comparison, the Pfizer-BioNTech vaccine has been found to be 97 percent effective, while Moderna has a 94 percent efficacy rate.

Health experts say Chinese vaccines are unlikely to be sold to the United States, Western Europe, and Japan due to the complexity of the approval process.

A Sinovac spokesman, Liu Peicheng, acknowledged that varying levels of effectiveness have been found but said that can be due to the age of people in a study, the strain of virus and other factors.

Beijing has yet to approve any foreign vaccines for use in China.  Gao gave no detail of possible changes in strategy but cited mRNA as a possibility.

“Everyone should consider the benefits mRNA vaccines can bring for humanity,” Gao said. “We must follow it carefully and not ignore it just because we already have several types of vaccines already.”

Gao previously questioned the safety of mRNA vaccines. He was quoted by the official Xinhua News Agency as saying in December he couldn’t rule out negative side effects because they were being used for the first time on healthy people.

As of April 2, some 34 million people in China have received both of the two doses required for Chinese vaccines and about 65 million received one, according to Gao.