London, Jul 20 (IANS): The UK government has signed deals for 90 million doses of promising coronavirus vaccines that are being developed, the media reported on Monday.

The vaccines are being researched by an alliance between the pharmaceutical companies BioNtech and Pfizer as well as the firm Valneva, reports the BBC.

The new deal is on top of 100 million doses of the Oxford University vaccine being developed by AstraZeneca.

However, it is still uncertain which of the experimental vaccines may work.

"The fact that we have so many promising candidates already shows the unprecedented pace at which we are moving," the BBC quoted Kate Bingham, the chair of the government's Vaccine Taskforce, as saying.

"But I urge against being complacent or over optimistic.

"The fact remains we may never get a vaccine and if we do get one, we have to be prepared that it may not be a vaccine which prevents getting the virus, but rather one that reduces symptoms," she added.

Meanwhile, Education Secretary Gavin Williamson, told the BBC on Monday morning that vaccine development was "an incredibly long process and we are doing it at breakneck speed" but that we should expect a COVID-19 vaccine "after winter".

The government is hoping to get half a million people to sign up to trials of vaccines in the UK through the NHS COVID-19 vaccine research registry website.

At least eight large scale coronavirus vaccine trials are expected to take place in the UK.