The World Health Organization has changed its stance on whether coronavirus can be spread through the air.
In updated guidance on the role of airborne droplets in transmission of COVID-19, the WHO said that airborne transmission of COVID-19 in crowded, indoor locations with poor ventilation “cannot be ruled out.”
Airborne transmission means that the virus could spread through particles known as aerosols, which can hover in the air after a person has left the area.
The organisation previously said that airborne transmission was a concern only in hospital settings during certain medical procedures, such as when patients are first put on breathing machines.
However, reports of outbreaks occurring in restaurants and fitness classes have suggested the possibility of airborne transmission, the WHO conceded.
But it said that other forms of transmission, such as through larger droplets released in coughs and sneezes and via contaminated surfaces, could still explain these clusters.
The change in guidance comes after more than 200 scientists called for WHO to acknowledge the coronavirus can spread in the air earlier in the week.
In a letter published in the Clinical Infectious Diseases journal, the collection of scientists wrote that studies have shown “beyond any reasonable doubt that viruses are released during exhalation, talking and coughing in microdroplets small enough to remain aloft in the air”.
The findings mean that people in certain indoor conditions could be at greater risk of being infected than was previously thought.
The experts referred to a Washington state choir practise and unpublished research about a poorly-ventilated restaurant in Guangzhou, China – each of which raised the possibility of infections from airborne droplets.
“We are concerned that the lack of recognition of the risk of airborne transmission of COVID-19 and the lack of clear recommendations on the control measures against the airborne virus will have significant consequences,” they wrote. “People may think they are fully protected by adhering to the current recommendations, but in fact additional airborne interventions are needed.”
The WHO has insisted that COVID-19 is spread via larger respiratory droplets, most frequently when people cough or sneeze, that fall to the ground.
Controversy has surrounded WHO guidance since the outbreak of the coronavirus pandemic.
Initially the body refused to recommend the use of face masks.
The UK government followed this advice but has now made face masks compulsory on public transport. In Scotland masks are mandatory in shops too.
And on Friday experts forecasted that if 95% of the population wear face masks in public the predicted coronavirus death toll in the UK could be reduced by up to 20,000 by the end of October.
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