A human cough simulator to investigate cough interventions and reduce environmental contamination
Using high speed back-lit video and a human cough simulator, scientists and photographers at the Health and Safety Executive (HSE) laboratory determined if cough related interventions reduce environmental contamination, protecting members of the public from infection.
A cough is known to transmit an aerosol cloud up to 2 m. During the 2020 pandemic the general public were encouraged by the United Kingdom’s National Health Service, other UK government agencies and the World Health Organization (WHO) to cough into their elbow. It was hoped that this would reduce the spread of Covid-19. There is limited evidence to support that cough mitigations such as this reduce viral spread.
The human cough simulator provided a standardised cough challenge loaded with a solution of simulated saliva and a SARS-CoV-2 surrogate virus; Phi6. Pseudomonas syringae. Settle plates were used to detect viable Phi6 virus following a simulated cough into a 4 × 4 m test chamber. The unimpeded pattern of contamination was compared to that when a hand or elbow was placed over the mouth during the cough. High speed back-lit video was also taken to visualise the aerosol dispersion.
Viable virus spread up to 2 m from the origin of the cough outwards in a cloud. The results also showed that interventions divert the cough cloud but do not appear to reduce environmental contamination and may in some cases increase the spread pattern. The use of a tissue or sleeve to absorb and catch some of the particles does appear to reduce the cough cloud.
It was shown that interventions can change the environmental contamination pattern resulting from a human cough but may not reduce it greatly.
More information
* Article: Simulating the Environmental Spread of SARS-CoV-2 via Cough and the Effect of Personal Mitigations
* Article in the HSE Annual Science Review 2022
* Link to videos on HSE Solutions website
* Email: buxton.infocentre@hse.gov.uk
Photo: High-speed backlit photograph of the Human Cough Simulator in the HSE Science and Research Centre laboratory: cough with a sleeved elbow
