Hundreds of thousands of people have taken an experimental COVID-19 vaccine developed by China National Biotec Group (CNBG) in the past two months, including Chinese subjects not enrolled in clinical trials, CNBG said.

China’s drug regulator authorized three experimental coronavirus vaccines for emergency use among those in high-risk groups such as medical workers, pandemic response officials, border inspection agents, and members of the military, though the final trials to prove that the vaccines are safe and effective are still underway.

China officially launched the emergency-use program in July, but certain state-owned companies started having their employees take the vaccine as early as June, workers told Caixin. CNBG, China’s leading coronavirus vaccine developer, said its product has proved to be safe and to have good immunogenicity in various animal tests, and the vaccine has obtained clinical study approval from China’s National Medical Products Administration, according to an informed consent form for emergency vaccination viewed by Caixin.

Now, emergency use of the vaccines is expanding. China’s civil aviation authorities recently provided vaccines for frontline workers at airlines and airports. Zheng Zhongwei, the head of China’s coronavirus vaccine task force, said the government is considering expanding the emergency program to cover transport industry officials, workers at produce markets, and service staff.

A COVID-19 vaccine made by Sinovac Biotech Ltd., a Nasdaq-listed Chinese vaccine developer, was also approved for emergency use. Yin Weidong, the company’s chairman and chief executive officer, told Reuters that 90% of its 3,000 or so employees and their families have been inoculated with the company’s vaccine candidate even though it hasn’t completed late-stage trials.

The hundreds of thousands of vaccine recipients can provide valuable data for evaluating the effectiveness and safety of vaccine candidates, but this data can’t be used as the basis for approving commercial application, said Yin, who added that he, his wife, and his parents have all received the vaccine. Sinovac is currently conducting Phase III trials in Brazil and Indonesia.

In an interview with Chinese state-owned television, Yu Xuefeng, the chairman and CEO of CanSino Biologics, another Chinese vaccine developer included in the emergency-use program, said commercial use must be supported by effective data from Phase III clinical trials.

China has been a global leader in the race to develop COVID-19 vaccines, contributing five of the nine vaccines that have reached late-stage Phase III trials. About 135 vaccine candidates are under development worldwide. Among them, about 10% use a traditional approach employing a weakened or inactive form of the virus, as does the CNBG candidate.

Starting in June, more than 1,000 employees of a Beijing-based state-owned company voluntarily received the CNBG vaccine, an employee of the Beijing company told Caixin. The person said he received the injection after the employer had repeatedly called for volunteers. The company requires all expatriate workers to take the vaccine before they can leave China, the person said.

Several other companies, including state-owned and private companies such as Huawei Technologies Co. Ltd., have started providing vaccines to staff, mostly to expatriate workers, according to employees at the companies.

CNBG said its vaccine was developed by a Beijing-based unit. According to publicly released progress reports, the vaccine was still in early phases of clinical safety trials when it started to be put into use. On April 27, the vaccine was tested in Shangqiu, a city in the central Henan province. On June 28, the company disclosed preliminary trial results showing that all participants produced antibodies against the COVID-19 virus within 28 days of receiving two doses of the vaccine.

Although Phase I/II clinical trials show that a vaccine induces neutralizing antibody responses, that’s not enough to prove it effectively protects patients, experts said.

Another informed consent form for emergency vaccination viewed by Caixin emphasizes that due to differences among recipients’ immune systems, it cannot be ruled out that certain people may not receive immune protection from the vaccine.

As with any other vaccine, the informed consent form listed common reactions that may occur after injection with the COVID-19 vaccine, including fever, headache, fatigue, nausea, diarrhea, muscle pain, joint pain, and lethargy. The employee of the state-owned company said recipients of the CNBG vaccine are required to report only fever.

CNBG said it signed agreements with Huawei and Phoenix Television, a partially state-owned television network, to provide resources and service support for routine and emergency vaccinations. CNBG is conducting Phase III trials abroad, including in the United Arab Emirates, Bahrain, Peru, Morocco, and Argentina.

Scientists said they aren’t sure how effectively these experimental vaccines can protect people from coronavirus infection.

“Since there’s no proven vaccine yet, any candidate that can help us prevent and control the pandemic is necessary,” said Xiong Sidong, president of Soochow University and director of the Institute of Biology and Medical Sciences.

The World Health Organization has warned that widespread immunization against COVID-19 may not be in the cards until the middle of next year.

This is an original article by Di Ning, Tang Hanyu, Jia Tianqiong, and Denise Jia of Caixin Global that has been republished with permission. You can find the original on Caixin’s website here.

(Header image: A woman holds a sample of the China National Biotec Group-developed COVID-19 vaccine at an exhibition in Beijing, Sept. 5, 2020. Zhang Lintao/People Visual)