The Chinese effort for a Covid-19 vaccine is heating up, as scientists continue to administer experimental doses of treatment to thousands of people in China daily.
Their effort's most recent challenge is from American pharmaceutical firm Pfizer, which said early data on its Covid-19 vaccine candidate suggests 90 per cent effectiveness in phase three clinical trials.
Chinese pharmaceutical firms Sinovac Biotech, Sinopharm and CanSino Biologics have been carrying out phase three clinical trials outside the country, and also giving out doses of the experimental treatment in their own country.
This, despite persistent concerns about the efficacy of the vaccines and the autonomy of those receiving the experimental treatments in China.
Most of them are workers in state-owned companies and students planning to go overseas.
According to Chinese state media, shots of four experimental vaccines - made by the three companies and in urgent use - have been administered to the people.
"Several of us were anxious to get back to our project abroad so my supervisor helped to rush the doctors to give us the shots earlier," said an engineer who works at a state-owned enterprise who declined to be named.
"Many of us are worried about the side effects because this is something we don't know anything about, but it felt incorrect to question it at the company... and all of us wanted to get back to work as soon as possible," he added.
He is usually based in a Middle Eastern country, but has had to stay put in Beijing since the pandemic broke out early this year.
Employees at state-linked enterprises said they were given a cocktail of two separate injections, administered several weeks apart.
So far, about 100,000 people have been inoculated with the Sinopharm vaccine. None has reacted badly to the treatment, said chairman Liu Jingzhen last Friday.
About 56,000 of them have travelled abroad and none has contracted the virus, he added, noting that they included employees of state-owned enterprises China National Petroleum Corporation and China Petrochemical Corporation and technology giant Huawei.
Besides their own country, the Chinese companies are also doing clinical testing in dozens of other nations, such as Indonesia, Brazil and Bahrain, because there are too few coronavirus cases in China for a large study.
Brazil's national health regulator yesterday allowed clinical trials of Sinovac's Covid-19 vaccine to resume, two days after an "adverse incident".
Public health officials said the "adverse incident" that led to the suspension - a volunteer recipient's death, which police are investigating as a suicide - had no connection with the vaccine, reported Agence France-Presse.
China yesterday reported two new cases, taking the number of active cases to 600. In all, the country's official tally is 92,304 cases.
Phase three clinical trials are important for vaccines because adverse side effects usually show up at this point in the experiments.
Meanwhile, in eastern China's Zhejiang province, thousands have payed 400 yuan (S$82) for an experimental dose.
Access to the vaccine will be formally expanded nationwide to high-risk groups such as medical workers as early as next month, China's Centre for Disease Control and Prevention's chief biosafety scientist Wu Guizhen told state television last month.
The Chinese authorities have cautioned that supply is limited. Priority will be given to doctors and nurses, delivery workers, overseas workers and others with specified employment needs.
