Filter could stop common cold

The device, invented by a Cornish pathologist, incorporates two small air filters that are placed in each nostril.

Researchers discovered the guard could block germs, including those that cause the common cold, as well as pollen, which leads to hay fever.

The device will make a "significant difference" in tackling a range of illnesses carried by the air including meningitis and tuberculosis, scientists said.

Occasional use

Researchers at Plymouth University were testing if the filters would block pollen spores.

"The guard is capable of filtering out the germs which cause viruses like the common cold," said Dr Martyn Polkinghorne, head of innovation at the university.

"It's not perfect, but this has the potential to make a significant difference in preventing colds."

The two connected filters form a horseshoe shape to fit into each nostril without affecting breathing.

The device would probably only be used occasionally in an environment where the chances of picking up a virus was high, he said.

"In practise how many people will want to put something up their nose all the time?," said Dr Polkinghorne.

"It is likely to be used in planes and in air conditioned buildings, where germs can spread easily."

Inventor Adrian Soper said: "We've changed the lives of people suffering from hay fever.

"We've had children who have never been able to go to the park in their lives, who are able to go, and women who have never had a bunch of flowers bought for them, who are now getting flowers from their husbands.

"I see no reason why the effects on the common cold should not be exactly the same."

Stocks of the filter have already sold out.

Mr Soper is arranging a deal with a manufacturer who plans to make 10 million of the guards, which will be sold across the world.