China's Centers for Disease Control (CDC) acknowledged the low efficacy of two COVID-19 vaccines produced by state-owned companies for the first time on Saturday.
Gao Fu, the director of China's CDC, said at a conference that two vaccines produced by Chinese companies Sinovac and Sinopharm “don’t have very high protection rates," The Associated Press reported while noting that the country's foreign ministry says nearly two dozen countries have accepted the vaccines for distribution.
He also said that officials are now considering the approval of other vaccines for distribution.
“It’s now under formal consideration whether we should use different vaccines from different technical lines for the immunization process,” he added, according to the AP.
The news service also reported that a second Chinese CDC official confirmed at a news conference Sunday that officials are conducting clinical trials of vaccines that use the messenger RNA (mRNA) process for delivery, as opposed to the inactivated vaccines released by Sinovac and Sinopharm, which use dead virus particles to stimulate immunity within patients.
“The mRNA vaccines developed in our country have also entered the clinical trial stage,” said the second CDC official, Wang Huaqing, according to the AP.
China's vaccine program has faced criticism from some U.S. officials who accuse Beijing of using donations of the two companies' vaccines for diplomatic purposes around the world while falsely touting the efficacy of the Chinese vaccines and disparaging vaccines made using the mRNA process, including those produced by Pfizer and Moderna.
A study by Brazilian health officials released in January found the Sinovac injection to be just above 50 percent effective at preventing cases of COVID-19.
Sinopharm has said that its vaccine is 79 percent effective at preventing COVID-19 infections, while a study conducted in the United Arab Emirates found it to be 86 percent effective.