Breathing or talking is ‘most common way to spread coronavirus’, scientists warn

JUST breathing or talking could be the "most common way to spread coronavirus", scientists have suggested.

Experts claim that evidence shows people with Covid-19 exhale millions of virus particles per hour - even if they have mild or no symptoms.

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The researchers, from the Center for Disease Control and Prevention in Beijing, say that it highlights the importance of wearing facemasks or face coverings in public.

So far, Brits have only been advised to wear on public transport or in public places such as supermarkets to prevent asymptomatic people from spreading the virus.

It was previously thought that the virus was mainly spread via droplets from coughs or sneezes.

But these latest findings suggest that transmission can be from something as simple as breathing.

This could explain how Covid-19 was able to sweep around the world so quickly.

For the new study, which was published online and is yet to be peer-reviewed by other scientists, researchers recruited 35 Covid patients.

They collected almost 300 viral samples from their breath, surfaces and air inside the hospitals.

The researchers, led by Professor Jianxin Ma, found on average there was three times the amount of virus in a patient's breath compared to on surfaces.

Their viral load was also four times higher than in air samples from hospital rooms and corridors.

Prof Ma said: "These observations do not support the widely-held belief that direct transmission by contact with surfaces plays a major role in Covid-19 spread."

Surface breakdown

The researchers looked at different types of surfaces to see if any were more contaminated than the others.

They found that toilets had the highest rate of SARS-CoV-2 - the virus which causes Covid-19 - at 16.7 per cent.

This was followed by hospital floors at 12.5 per cent and bins, doors and handrails at four per cent.

Scientists were surprised to find that just two out of 22 swabs taken from mobile phones had detectable levels of the virus.

They added: “Large respiratory droplets and direct contact transmissions are presently cited as major transmission routes for the Covid-19.

“Evidence from our work show that exhaled breath emission may well be the most significant SARS-CoV-2 shedding mechanism, which could have contributed largely to the observed cluster infections and the ongoing pandemic.

"Accordingly, measures such as enhanced ventilation and the use of face masks are essential to minimise the risk of infection by airborne SARS-CoV-2."

Age influence

The researchers also noted that the amount of virus exhaled depended on the stage of their illness as well as their age.

They found that the breath emission rate was highest within three days of showing symptoms - at 105 viral particles per minute.

Previous reports have also shown that viral load in throat swabs was higher at this point.

Researchers also suggest that those aged over 50 exhale more of the virus than younger people.

However, they would need to test a larger sample to be certain.

It comes just weeks after a study revealed that speech droplets generated by asymptomatic carriers of the illness is a mode of transmission.

The study, published in the Proceedings of the of Sciences in the US, used sensitive laser light scattering observations that revealed that loud speech can actually emit thousands of droplets per second.