The Nobel Prize committee said: "The laureates contributed to the unprecedented rate of vaccine development during one of the greatest threats to human health in modern times."

Traditional vaccine technology has been based on dead or weakened versions of the original virus or bacterium - or by using fragments of the infectious agent.

The immune system recognises these as foreign so it attacks and has learned how to fight the virus, and therefore has a head start when future infections occur.

The big idea behind the technology is that you can rapidly develop a vaccine against almost anything - as long as you know the right genetic instructions to use.

But by refining the technology, the researchers were able to produce large amounts of the intended protein without causing dangerous levels of inflammation that had been seen in animal experiments.

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