Chinese scientists working on a COVID-19 vaccine have told Sky News they are "99%" sure it will be effective.
Sinovac, a Beijing-based biotech company, currently has its coronavirus vaccine in stage 2 trials, with more than 1,000 volunteers participating. Sky News is the first British broadcaster to visit its labs.
The company also said it is in preliminary talks to hold stage 3 trials - the final part of the trials process - in the UK.
Sky News asked Luo Baishan, a researcher at Sinovac, whether he thought the vaccine would be successful.
"Yes, yes. It must be successful… 99% [sure]," he replied.
Last month Sinovac published results in the academic journal Science which showed the vaccine, called CoronaVac, protects monkeys from infection by the coronavirus.
The biggest problem the company faces is the low number of COVID-19 cases in China, which makes testing the vaccine in an epidemic situation difficult. As a result, the company is looking further afield for stage 3 trials.
Helen Yang, senior director of investor relations, told Sky News: "We are speaking to several European countries and I think did discuss with the UK as well.
"Currently it's a very preliminary stage for the discussion."
The company is pressing ahead with production, though, even as it continues research.
In the company's headquarters in northwest Beijing, orange and white packets are already ready to go.
The aim of parallel tracks is that mass production of the vaccine can begin straight away, if the trials are successful and the vaccine gets regulatory approval.
It is currently building a commercial plant in another part of Beijing with the objective of delivering 100 million doses.
That number, large as it is, means limiting who gets the vaccine.
"It is our recommendation that it is not the whole population that gets the vaccine," Ms Yang told Sky News.
"We are discussing this and recommending it to other countries as well.
"We are firstly targeting high-risk groups, for example, health workers or senior citizens, who may have a higher level of fatality rate. I think that will be the starting point. To be frank, the vaccine needs to be produced lot by lot."
And the vaccine won't be here soon. The stage 2 trials have months to run before Stage 3 can begin, Ms Yang pointed out, and then the vaccine requires regulatory approval.
Asked whether she was sure of success, Ms Yang told Sky News: "It's very hard to say, very difficult to say at the moment. There are uncertainties, but the data: so far, so good."
There is a global race to come up with a COVID-19 vaccine - but questions remain about how it would be distributed, and whether countries should prioritise their own populations.
Drugmaker AstraZeneca, which is working with researchers at Oxford University, said the UK would be the first country to get access to the vaccine it is developing.
Chinese President Xi Jinping has pledged that any Chinese vaccine would be a "global public good", even though the practical results of that are unclear. EU leaders have made a similar commitment, but US President Donald Trump has not.
Ms Yang told Sky News: "We are already considering not only China but also the whole world, not only for conducting a trial but also how to supply a solution for countries including China and outside China."
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