Researchers found that coughing produces 10 times more infectious ‘aerosol’ particles compared to speaking or breathing.
There are now calls for healthcare workers, who are already up to four times more likely to contract coronavirus than the general population, to be given FFP3 respirator masks and to improve hospital ventilation.
The infection rates among general hospital staff are almost double those of intensive care unit workers who have access to full PPE.
Some of the frontline health workers who have died with coronavirus during the pandemic
Coughing coronavirus patients are putting frontline NHS staff at greater risk of catching the virus than first thought, according to a new study (stock image)
While employees in other hospital areas, GP surgeries and care homes are given surgical masks which stop the larger virus-carrying droplets, they do not always keep out the aerosol particles.
It was previously assumed that ICU wards were more dangerous as some treatments used to support the breathing of Covid patients, like continuous positive airway pressure (CPAP), would generate large quantities of these tiny molecules.
But the latest research led by Dr James Dodd, a consultant senior lecturer in respiratory medicine at North Bristol Lung Centre and the University of Bristol, claims it is the opposite way around.
Dr James Dodd, a consultant senior lecturer in respiratory medicine at North Bristol Lung Centre and the University of Bristol, who led the research
‘CPAP is not aerosol-generating – in fact, the aerosols are reduced compared to just normal breathing and speaking,’ he told the Guardian.
‘However, cough really is a potent generator of aerosols. [The risk] appears to be far greater than what we would have assumed.’
Healthy volunteers were recruited for the study to receive CPAP or high flow nasal oxygen in a well-ventilated operating theatre.
This allowed Dr Dodd and his team to measure the exact aerosols produced without the interference of background particles and measurements were taken when the volunteers spoke, breathed and coughed normally.
And for the first time, the researchers separately measured the aerosol emissions from coronavirus patients.
At least 10 times more aerosol particles were produced while coughing than speaking or breathing. All of these generated more airborne molecules than CPAP and even in cases when the volunteers wore a surgical mask.
The emission of aerosol particles were similar between coronavirus patients and the healthy participants.
The findings from the study, not yet peer-reviewed, have been presented to the National Institute for Health Research’s aerosols group which reports to Sage.