New evidence on the airborne transmission of COVID-19 will not force pubs and restaurants to close their doors once again, according to an infectious disease expert.

Nearly 240 top scientists in 32 countries have signed an open letter calling on the World Health Organisation to acknowledge that the virus may be spread by tiny particles suspended in the air.

The organisation has previously said the virus is primarily spread by large respiratory droplets that come from coughing and sneezing.

It is refusing to update its official advice, citing a lack of “definitive” evidence; however, it has admitted that it can’t rule out airborne transmission.

On The Pat Kenny Show this morning, infectious disease specialist at the Mater Hospital in Dublin said there is no need to change public health advice, even if the virus is airborne.

“The guidance is you need a mask,” he said. “The mask will prevent that. If you are in an enclosed space, six feet away from somebody and it is aerosolised, the virus is going to jump seven feet or eight feet so social distancing is not going to work.

“A mask will work. It is that simple.”

He said the situation should remain largely the same for indoor spaces like pubs and restaurants.

“If 100% of all the servers are wearing masks themselves and if we use one metre, we use masks when we are not eating and drinking and we minimise the time in these restaurants [it is not doomed to fail],” he said.

“Yes, it is an experiment. Will it fail? It will fail if people are not wearing masks and all of the servers are running around with no masks on – which they are in some locations in Dublin at the present time.

“I think we actually shouldn’t fight over one versus two metres. I think we have to put together the whole plan and that is making sure there are masks, making sure there are hand washing facilities and making sure there is a safe distance and short periods of time in those locations – and we will see what happens.

“That is the only solution.”