Government scientist says 2m social distancing rule based on ‘very fragile’ evidence

One of the top scientific advisers to the British Government said the two metre (6’6″) social distancing rule is based on ‘very fragile’ evidence.

People in the UK have been urged to stay at least 2m, or six-and-a-half feet, away from anyone who they don’t live with, to avoid catching or spreading COVID-19.

But the distance may be a non-scientific estimate that just caught on in countries around the world, as top researchers say there is not solid evidence to back it up.

Professor Robert Dingwall, a sociologist at Nottingham Trent University and a member of government advisory group NERVTAG (New and Emerging Respiratory Virus Threats Advisory Group) made the comments this morning.

He said that the World Health Organization and other countries in Europe had reduced this distance to one metre but the UK is persisting with the full 2m.

Professor Dingwall said BBC Radio 4 today: ‘The World Health Organization recommends a one metre distance, Denmark has adopted it since the beginning of last week.

‘If you probe around the recommendations of distance in Europe you will find that a lot of countries have also gone for this really on the basis of a better understanding of the scientific evidence around the possible transmission of infection.’ 

Iain Duncan-Smith, a former Conservative Party Cabinet minister has also called for the rule to be relaxed, saying it will be impossible to maintain in pubs and restaurants. 

People in the UK still face rules dictating that they must stay at least 2m (6'6") away from anyone who doesn't live in their household (Pictured: Shoppers in a socially-distanced queue outside a Tesco supermarket in Birmingham)

People in the UK still face rules dictating that they must stay at least 2m (6’6″) away from anyone who doesn’t live in their household (Pictured: Shoppers in a socially-distanced queue outside a Tesco supermarket in Birmingham)

Professor Dingwall has spoken out about the weakness of the two-metre rule in the past, suggesting it could safely be cut at least to 1.5m.

He has even suggested that it is being clung to by British officials because they don’t feel they can trust the public to manage a shorter distance. 

Speaking to The Telegraph earlier this month Professor Dingwall said: ‘There is a fair degree of consensus now among people who are more expert on these things than I am that outdoor transmission is negligible…

‘Personally I think we could quite safely go to 1.5metres, which seems to be an internationally acceptable standard, inside and outside.’

Professor Robert Dingwall, a sociologist and adviser to the government, has referred to the 2m rule as 'a rule of thumb'

Professor Robert Dingwall, a sociologist and adviser to the government, has referred to the 2m rule as ‘a rule of thumb’

He added that officials had told him they ‘did not think the British population would understand what one metre was and we could not trust them to observe it so we doubled it to be on the safe side’.

And in further comments made to Radio 4 in April, Professor Dingwall said it would be harder to enforce rules without scientific evidence. 

‘I think it will be much harder to get compliance with some of the measures that really do not have an evidence base,’ he said. ‘I mean the two-metre rule was conjured up out of nowhere.’ 

He referred to it as a ‘rule of thumb’ rather than a scientifically proven measure. 

Although the British Government has loosened some of its lockdown restrictions, such as allowing people to spend as much time outside as they want to, everyone is still required to stick to the social distancing rule.

Lines on supermarket floors to keep shoppers apart, spaced out queues outside shops and takeaways and walking in the road to get round people on then pavement are now commonplace.

What is the science behind two-metre social distancing rule?

There are a wide range of recommendations on social distancing that differ from country to country.

The World Health Organisation recommends a one metre distance between two people from separate households. 

The reason for this, as stated on its website, is that: ‘When someone coughs, sneezes, or speaks they spray small liquid droplets from their nose or mouth which may contain virus. If you are too close, you can breathe in the droplets, including the COVID-19 virus if the person has the disease.’

But other countries have taken advice from their own health experts and social distancing varies from two metres (in the UK) down to one metre (in France)

The two metre rule can be traced back to research in the 1930s that showed droplets of liquid from coughs or sneezes would land within a one-two metre range, as reported by the BBC.

Iain Duncan Smith is not the first to criticise the UK’s adopting of the two metre rule, out of line with many other European countries.  

Robert Dingwall, from the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag), previously said in April the rule was ‘conjured up out of nowhere’. 

Mr Dingwall told Radio 4’s Today: ‘We cannot sustain [social distancing measures] without causing serious damage to society, to the economy and to the physical and mental health of the population.

‘I think it will be much harder to get compliance with some of the measures that really do not have an evidence base. I mean the two-metre rule was conjured up out of nowhere.’ 

Social distancing varies between different countries: 

TWO METRES: UK, Switzerland, US, Spain, Italy

1.5 METRES: Germany, Poland, Netherlands

ONE METRE: Austria, Norway, Sweden, Finland

The thinking behind the rule is that it dramatically reduces the risk of virus droplets being able to jump between people.

The coronavirus spreads on invisible droplets of fluid that are expelled from someone’s mouth and nose when they breathe out, cough or sneeze.

If someone else breathes them in they will catch the infection when the virus latches on to cells in their airways.

Over the space of two metres the vast majority of these particles drop to the floor, away from potential victims, scientists say.

Former Conservative Party leader, Iain Duncan-Smith, has also urged the government to drop its two-metre rule so hospitality staff can return to work.

He said on Radio 4’s Today programme yesterday: ‘We’re the only country certainly in Europe that I know of [that uses the two-metre rule]…

‘I think when it comes to the hospitality sector, I think we do need to look at it very carefully.

‘So we do need to look at how they manage that process and give them some flexibility.’

The cautious two-metre rule is actually used in Switzerland, the US, Spain and Italy, as well as in the UK.

While detractors say it is an unnecessarily large distance, experts suggest that the risk of catching the virus is considerably higher at one metre than it is at two.

Andrew Curran, chief scientific adviser at the Health and Safety Executive said being exposed to someone for ‘a few seconds’ at a one metre distance could equate to around an hour of being two metres away from the same person, the Sunday Telegraph reported.

He said: ‘If the exposure at a distance of less than two metres is going to be for a short period of time, you manage the risk in the context of duration and orientation.

‘There is some physics in this and the Sage sub-group is looking at that to provide better information.

‘For example, if you were exposed for a few seconds at one metre, that is about the same as being exposed for a longer period of time – an hour, say – at two metres. It is that order of magnitude.

‘There may be elements within a job where there is exposure for a short period, but where the risk is so low it can be managed.’

ONE METRE FOR A FEW SECONDS ‘IS AS RISKY AS AN HOUR AT TWO METRES’

Spending a few seconds one metre from a colleague is equivalent to an hour two metres away, and talking loudly makes it worse, experts warn.

Government scientific advisors are considering telling workers exactly how strong the risk of catching the coronavirus is depending on how close they stand next to someone.

The fresh advice would help employees ‘manage’ their risk of the killer infection where social distancing is difficult.

Companies are wrestling with new safety rules to allow employees to return to work as Prime Minister Boris Johnson sets out steps to restart the economy.

Social distancing is paramount, but there are growing concerns this won’t be possible for some employees in confined spaces, including construction site workers.

Pictured, construction workers in south London on May 12. People in manual jobs may find it harder to social distance at work

Pictured, construction workers in south London on May 12. People in manual jobs may find it harder to social distance at work

Ministers are hoping for a gradual re-opening of schools from June 1, but there are fears children will be unable to properly social distance.

It follows a study last week that showed talking loudly for just one minute can produce a high load of viral particles that stay in the air for eight minutes.

Other simulations show how far infected particles from a cough or sneeze can travel in confined spaces.

Employers in the UK have been told to re-design workspaces to ensure workers are at a two metre distance from others as much as possible.

The new ‘COVID-19 secure’ guidance covers eight workplace settings which are allowed to be open, including construction sites, factories and takeaways.

Where social distancing is difficult, there should be barriers in shared spaces, staggered start times and one-way walking systems, the guidance says.

But where social distancing is seemingly impossible, a sub-group of the Scientific Advisory Group for Emergencies (SAGE) is examining how workers can ‘manage’ the risk, the Sunday Telegraph reports.

Andrew Curran, chief scientific adviser at the Health and Safety Executive said being exposed to someone for ‘a few seconds’ at a one metre distance could equate to around an hour of being two metres away from the same person.

He said: ‘If the exposure at a distance of less than two metres is going to be for a short period of time, you manage the risk in the context of duration and orientation.

‘There is some physics in this and the Sage sub-group is looking at that to provide better information.

‘For example, if you were exposed for a few seconds at one metre, that is about the same as being exposed for a longer period of time – an hour, say – at two metres. It is that order of magnitude.

‘There may be elements within a job where there is exposure for a short period, but where the risk is so low it can be managed.’

Two metres is considered a safe distance by health chiefs because the coronavirus predominantly spreads in respiratory droplets in a sneeze or cough.

These large droplets fall to the floor due to gravity within a short distance, around one metre, from the person who expelled them. The ‘safe’ distance is double that in order to optimise protection.

Two metres is not a ‘magical number’ according to John Simpson, a medical director at Public Health England.

He said ‘there is a duration and distance element to exposure that has to be worked through’, as scientists continue to work out how the coronavirus spreads in different conditions.