Covid: No proof that plastic screens stop coronavirus transmission in pubs or workplaces, SAGE says

Plastic screens used in pubs and workplaces are unlikely to help in stopping Covid transmission, Government scientists have said. 

New guidance after ‘Freedom Day’ told employers to consider placing screens and barriers between workers to curb transmission.

But in a paper published by SAGE today, researchers warned screens could actually increase transmission rather than prevent it.

Covid spreads in tiny liquid particles which are released whenever infected people cough, sneeze, speak or breathe.   

The paper said screens could help stop the virus being spread by two people sitting face-to-face no more than two metres (6ft 6in) apart.

But they offered little protection to people sat further away because the virus ‘easily pass around a screen with the airflow in a short period of time’.

The authors wrote: ‘There is some epidemiological and mechanistic evidence that suggests screens could increase risks of aerosol transmission due to blocking or changing airflow patterns or creating zones of poor air circulation behind screens. 

‘Screens are unlikely to provide any direct benefit in reducing exposure to the virus from droplets or aerosols when people are already located at two metres or greater or where they are not face to face.’ 

The findings come amid confusion over how employers should set up the workplace for the return of staff over the coming weeks. 

Documents released online just days before the July 19 unlocking suggested offices keep social distancing measures like plastic screens and back-to-back desks in a bid to placate nervous workers. 

Plastic screens used in pubs and workplaces are unlikely to help in stopping Covid transmission, Government scientists have said

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Documents released online just days before the July 19 unlocking also suggest workplaces keep social distancing measures like plastic screens and back-to-back desks in a bid to placate nervous workers

The SAGE paper, which was written before ‘Freedom Day’, suggested more research needs to be done on screens to determine how useful they are.

It said: ‘There is very little data on the effectiveness of screens and barriers at reducing infection transmission from epidemiological, modelling or laboratory studies.’ 

But it did suggest with ‘medium confidence’ that screens could increase the risks of transmission by producing areas of poor air circulation.

Screens are effective at preventing large droplets transmitting between people less than two metres apart.

But they have very little benefit in preventing small aerosol spreading around rooms.

The scientists said that whether the screens are effective will depend on layout of the space, the ventilation, the size and design of the screen and the interactions that happen in the environment.

They added: ‘There are large numbers of screens that are unlikely to be effective due to their design or positioning.’

The experts said further research is needed to look at the effectiveness of screens and barriers in real-world settings.

They also said it is unclear whether screens or barriers can act as reminders to people to maintain social distance or help organisations manage the layout in their environments.

The experts said: ‘It is also possible that screens could provide false assurance, although studies have shown that there is very little evidence of risk compensation behaviour.

‘Further research is needed to understand whether there are any behavioural influences of screens and barriers.’

Screens in workplaces are not mandated by No10 but they are part of a series of measures recommended by the Government.

Employers and unions hit back at the confusing guidance, arguing no set rules on social distancing, mask wearing and whether to use screens, regular testing or temperature checks was a ‘recipe for chaos’.