The vaccine, the first approved for general use in China, is crucial to Beijing as it struggles to keep the outbreak contained and deflect criticism of its handling of the virus, which emerged in Wuhan in late 2019.
Yet the lack of detail released by regulators and Sinopharm has raised concerns. On Wednesday, the CNBG reported results based on interim analysis from Phase 3 trials. In a brief statement on the website of the Beijing Institute of Biological Products, a CNBG unit, the company did not give key specifics, including the sample size tested or number of infections in the trial or side effects.
“It is concerning about the missing information,” said Xi Chen, an associate professor of public health at Yale University.
The shot is one of two developed by Sinopharm, whose vaccines have already been used on almost 1 million Chinese citizens as of November under an emergency use program for high-risk groups, according to the company’s chairman.
“This is a much larger-scale trial than Oxford-AstraZeneca. The Chinese government might be more confident, given Sinopharm’s much larger number of recipients,” Chen said. “However, it is still critical to gain market confidence by releasing adequate clinical trial data.”
CNBG president Wu Yonglin said Thursday that detailed data would be released later after more observation and would be published in scientific journals in China and overseas. The company said the dosage regimen proved “safe” and that those who received it produced a high level of antibodies against the virus.
Chinese health officials said Thursday that a total of more than 4.5 million doses of coronavirus vaccine have been given to Chinese citizens. According to Zeng Yixin, vice minister of China’s National Health Commission, fewer than 0.1 percent of recipients developed a fever, and 0.2 percent experienced allergic reactions.
“This fully proves our vaccines are safe,” Zeng said.
As coronavirus cases surge globally, a huge emergency vaccination drive is underway, with drug developers and governments racing to get their vaccines approved. On Wednesday, the British government said its regulator had approved a vaccine developed by the University of Oxford and AstraZeneca.
The Sinopharm vaccine appears to be less effective than those developed by Moderna and Pfizer-BioNTech, which have shown an efficacy rate of 95 percent. According to interim data, the Oxford-AstraZeneca vaccine was 62 percent effective for those given two full doses. The vaccine was 90 percent effective for a subgroup that received a half dose followed by a full dose, but British regulators said the results of a half-dose regimen could not yet be supported.
The efficacy rate announced by Sinopharm is also lower than the 86 percent rate reported by officials in the United Arab Emirates after clinical trials conducted there. Sinopharm did not release data accounting for the discrepancy.
The approval and rollout of the Sinopharm vaccine will bolster China’s public health diplomacy drive.
In May, Chinese President Xi Jinping pledged to make homegrown vaccines a “global public good.” Beijing has held up its vaccines as a key part of its partnerships with developing countries, many of which have struggled to buy supplies of other newly released vaccines. The Sinopharm vaccine has been approved for use in the United Arab Emirates and Bahrain.
“China’s attention is not on ‘vaccine race,’ let alone so-called ‘vaccine diplomacy,’ but on the common interests of all humanity,” the state-run Global Times said in a Dec. 14 editorial.
Both Sinopharm vaccines use an inactivated version of the virus to trigger an immune response, unlike the mRNA vaccines developed by Pfizer and Moderna, which use new technology. It does not need to be frozen, making for easier storage and distribution.
Sinopharm, one of China’s largest drugmakers, said in October that it may be able to produce 1 billion doses by the end of 2021.
China is battling clusters of new locally transmitted coronavirus cases and working to keep the virus contained ahead of the Lunar Near Year holiday, when hundreds of millions of people crisscross the country. Health officials said they plan to vaccinate 50 million people in China by mid-January, before the holiday begins.