Staying two metres apart is twice as safe as one metre
Strict social distancing, eye protection and face masks slash risk of infection, WHO study finds
KEEPING two metres apart from someone with coronavirus is twice as effective as one metre, the first comprehensive review into social distancing has found.
The international analysis of dozens of studies, prepared for the World Health Organisation, concluded that a one-metre distance left people at three per cent risk of contagion, but that the risk roughly halves at two metres.
The review, published in The Lancet, could have major implications for tentative government plans to ease the lockdown further.
Pubs and restaurants will be among the last sectors to be allowed to reopen, possibly next month, principally because of the difficulty of adhering to the Government’s two-metre rule.
Ministers have faced repeated calls to relax the rule, with critics pointing out that authorities in Germany insist on only 1.5 metres.
Scientists generally agree that Covid-19 is spread mainly through large droplets emitted by carriers coughing or sneezing. These are thought to fall to the ground relatively quickly after leaving the body.
However, there is far more uncertainty over whether the virus can remain in the air in aerosolised form, and if so for how long.
For the new study, an international group of scientists analysed data from research into Covid-19, SARS and Mers viruses, involving 7,782 participants.
The risk of infection when people stand more than a metre away from the infected individual was found to be three per cent, and 13 per cent if within a metre.
Prof Holger Schunemann from Mcmaster University in Canada, who coled the research, said: “Our findings are the first to synthesise all direct information on Covid-19, SARS, and Mers, and provide the currently best available evidence on the optimum use of these common and simple interventions to help ‘flatten the curve’ and inform pandemic response efforts in the community.
“Governments and the public health community can use our results to give clear advice for community settings
‘There have been complaints that two metres is excessive because it is more than in other countries. But this review supports it’
‘This is going to be very difficult in some settings but is important and we’ll all need to get used to maintaining this distance for some months to come’
and healthcare workers on these protective measures to reduce infection risk.”
The team also analysed 13 studies focusing on eye protection found that face shields, goggles, and glasses were associated with lower risk of infection, compared with no eye covering.
They found that the risk of infection or transmission when wearing eye protection was six per cent, and 16 per cent when not wearing eye protection.
Evidence from 10 studies also found similar benefits for face masks in general. There was a three per cent risk of infection or transmission when wearing a mask and 17 per cent risk without.
However, researchers said that there was a low level of certainty around face mask and eye protection evidence.
Prof Linda Bauld, Professor of Public Health, University of Edinburgh, who did not take part in the study, said:
“The first and probably the most useful finding is that physical distancing matters.
“There have been plenty of complaints that the guidance in the UK on two metres distance is excessive because it is more than in other countries.
“But this review supports it. Maintaining this distance is likely to reduce risk compared with one metre.
“Thus where possible, this is the distance that retailers and employers should use as more premises and workplaces reopen in the future.
“This is going to be very difficult in some settings but is important and we’ll all need to get used to maintaining this distance for some months to come.”
Food service providers, pubs and hotels will be able to open from July 4, along with hairdressers, churches and leisure facilities such as cinemas.
The advice makes clear that this last group must “meet the Covid-19 secure guidelines” and, if they cannot do this, they might not be allowed to reopen.
The document says: “Some venues which are, by design, crowded and where it may prove difficult to enact distancing may still not be able to reopen safely at this point, or may be able to open safely only in part.”
Researchers said that none of these interventions – even when properly used and combined – offered complete protection from infection.
The study, which was carried out to inform WHO guidance documents, looked at the available evidence from the scientific literature and is the first time researchers have systematically examined the optimum use of these protective measures in both community and healthcare settings for Covid-19.