Scientists have warned that hairdressers and barbers could be unknowingly spreading Covid-19 because visors are not giving them enough protection – urging them to use masks instead.
They have warned government ministers that the current guidance of wearing just a visor could be allowing airborne droplets to pass under the PPE.
Now they are calling for the guidance to barbers and hairdressers to be updated so that they wear masks and visors.
Concerns were raised at the latest meeting of The New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) on Friday.
The concerns were also discussed at a sub-committee of the Scientific Advisory Group for Emergencies (SAGE), the Daily Telegraph reports.
Prof Mark Wilcox, a professor of medical microbiology who attends Sage and two of its sub committees, said: "I don't think the guidance is correct and I don't understand why visors were chosen in preference to masks.
"We have, in several settings, discussed the issue of masks versus visors and I think it would be fair to say that I am not alone in these views. My colleagues both in those settings and in other settings share my views.
"I've not come across somebody who has said that visors are the best thing."
Dr Ben Killingley, a consultant in infectious diseases who sits on Nervtag, said: "I don't know where it came from, where someone decided that just wearing a visor for hairdressers alone would be enough. That doesn't make sense to me.
"A visor is primarily worn to protect workers from splashes. It does the same job as goggles, protecting the eyes. No healthcare worker would ever wear a visor without a mask.
"You would have thought for their own protection and just in case they have been infected themselves, they should be wearing a mask themselves. In my view, both to protect the hairdresser and the person coming in, just wearing a visor alone is not enough."
At the moment the government advice says: "Clearly, when providing close contact services, it often may not be possible to maintain social distancing guidelines (2m, or 1m apart with risk mitigation, is acceptable).
"As a result, personal protective equipment in the form of a visor will be required to mitigate the risk."