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Britain's two-metre social distancing rule 'is based on outdated science'

Britain’s two metre social distancing rule is based on outdated science and is not far enough in crowded places like bars, experts say.

Dr Nicholas Jones and colleagues at the University of Oxford said the rule was produced from studies dating back up to 100 years ago and is too simplistic.

Instead, there should be a grading system depending on how ‘risky’ a place is, they said.

Evidence suggests that how far virus-carrying droplets can spread from a cough or sneeze depends on the environment around them. 

A bar, pub or nightclub would be deemed high risk because it is indoors, poorly ventilated and people have to shout to be heard over music. Therefore it should have more stringent distancing rules, the researchers argued.

But in places deemed to be low risk such as parks, the rules can afford to be relaxed, which would ‘potentially enable a return towards normality in some aspects of social and economic life’.

Scientists have previously argued the two-metre (6’7″) rule is not based on evidence but, in contrast to Dr Jones, were in favour of scrapping it.

Britons are told to distance themselves two metres from others, but in England and Northern Ireland this was reduced to ‘one metre plus’ in July in order to help pubs, restaurants and shops re-open. 

The ‘plus’ refers to other efforts people should make to put barriers between themselves and others, such as not being face-to-face, screens, or face coverings. 

The two metre physical distancing rule is based on outdated science and should be extended in crowded places like bars, experts have argued. Pictured: A group of drinkers enjoy the atmosphere in Manchester with takeaway pints of beer, July 4

The two metre physical distancing rule is based on outdated science and should be extended in crowded places like bars, experts have argued. Pictured: A group of drinkers enjoy the atmosphere in Manchester with takeaway pints of beer, July 4

A policeman keeps watch over the large crowds that gathered on the street in the middle of Soho in London, July 4

A policeman keeps watch over the large crowds that gathered on the street in the middle of Soho in London, July 4

The researchers made a graphic to show the risk of SARS-CoV-2 transmission from people who do not have symptoms in different settings. A bar would be under 'high occupancy, poorly ventilated, and without face coverings, showing even when no one is speaking, there is still a high risk

The researchers made a graphic to show the risk of SARS-CoV-2 transmission from people who do not have symptoms in different settings. A bar would be under ‘high occupancy, poorly ventilated, and without face coverings, showing even when no one is speaking, there is still a high risk

Social distancing is vital for reducing the spread of Covid-19 but is a contentious issue because it puts strain on the economy and relationships.

Dr Jones, a GP and researcher at the Nuffield Department of Primary Care Health Sciences, said the two metre rule can be traced back as far as 1897 and was supported by a range of studies in the 20th Century.

THE TWO-METRE RULE: WHEN AND WHY WAS IT IMPLEMENTED? 

Social distancing rules, one of the main ways to prevent the spread of Covid-19 in the absence of a vaccine, have been highly debated during the pandemic.

Although they are crucial for curbing the coronavirus, policy makers have to consider the implications they have on the economy.

In June, as the British hospitality sector prepared to open again, the Prime Minister Boris Johnson came under pressure from groups representing pubs, bars and the like to shorten the physical distancing rules.

It would allow more people into the venues and potentially save hundreds of venues – and their staff – going bust after months of lockdown.

Figures from the British Beer and Pub Association figures showed that with the two metre rule, only 20 to 30 per cent of premises will be able to open at a sustainable level. However, if the rule was reduced to one metre, 70 per cent would be able to open.

The Prime Minister ordered a ‘comprehensive’ review of the measure, in light of dwindling infection rates at the time.

From July 4, the rule in England was changed to ‘one metre plus’ – meaning the addition of face masks were necessary if people stood only onne metre apart. 

Northern Ireland adopted the same change from Monday, 29 June but Scotland and Wales haven’t announced any changes to the two-metre rule. 

Among those who do not agree with the two metre rule are two University of Oxford experts who argued in mid-June there is little proof to support the restriction.

They reviewed a World Health Organisation (WHO) paper on the contentious topic, which concluded keeping one metre apart can slash the risk of catching coronavirus by 80 per cent. There was roughly a 1.3 per cent chance of contracting the virus when two metres from an infected patient. But halving this gap raised the risk to only 2.6 per cent.

Oxford professors Carl Heneghan and Tom Jefferson said of 38 studies, only one looked specifically at coronavirus infections in relation to a specific distancing measure of two metres — and it found it had no effect.

The pair of scientists claimed the evidence in favour of the two-metre rule is of ‘poor quality’ and impacting Britain’s chance to go about normal daily life.

Former Cabinet ministers Iain Duncan Smith and Greg Clark were among the senior figures calling for an overhaul to the social distancing guidelines in June.

They pointed out that other countries were using lower limits – including Germany and the Netherlands following 1.5 metres, and Austria and Sweden following one metre – which is sufficient, according to the WHO.

But Professor Chris Whitty, the popular Chief Medical Officer, and Chief Scientific Adviser Sir Patrick Vallance reportedly made it clear they believe the guidance on safe distancing should have stayed.

The Sunday Times claimed Downing Street was concerned at the scale of opposition among scientists, who feared relaxing social distancing could lead to a second spike in coronavirus infections.

Despite the limitations of these early studies, they ‘assumed the scientific basis’ of the one/two metre rule now. 

The paper noted a landmark review commission by the World Health Organization, which supported a one-metre-or-more rule to limit Covid-19 spread. 

It was heavily based on data from the coronaviruses SARS and MERS, which are related to the virus that causes Covid-19 but are different and less deadly.

Scientists have previously said the WHO review used data of ‘poor quality’.

Another recent review of ten studies found eight showed projection of respiratory droplets beyond two metres – and even as far as eight metres (26ft) in one study.

Respiratory droplets are the main route of Covid-19 transmission, according to the World Health Organization (WHO). 

Large droplets only travel short distances before falling to the floor, which is why it the ‘safe social distance’ recommended between people is two metres.

Aerosols, on the other hand, are small and can linger in the air for longer and travel further.  

It is not clear yet if Covid-19 is airborne, but emerging evidence suggests it may play a role and is being reviewed by the WHO.  

Dr Jones and colleagues said the two-metre rule is based on viral transfer by either large droplets or small airborne droplets emitted in isolation.

It does not account for the exhaled air that comes with coughing, sneezing, talking singing or panting – in a gym, for example.

All these generate warm, moist, high momentum gas clouds of exhaled air, which helps to move droplets faster than if they were isolated, keeps them concentrated, and can extend their range up to eight metres within a few seconds, the paper warned.

‘Clouds of small droplets can travel beyond two metres in the air, and even large droplets have enhanced range,’ the paper in the British Medical Journal said.

‘Rules… are based on an outdated, dichotomous notion of respiratory droplet size.’  

Transmission is also impacted by the environment – including type of activity, indoor versus outdoor settings, level of ventilation and whether face coverings are worn.  

Indoor case clusters have been reported within fitness gyms, boxing matches, call centres, and churches, where people might sing, pant, or talk loudly.

But they have not been linked with airplanes, where people are relatively silent.

Meanwhile an outbreak of cases at a Chinese restaurant was blamed on the ventilation, helping to spread the virus around. 

And outbreaks in food factories have been attributed to a combination of cold conditions, poor ventilation, cramped working conditions, and background noise – which leads to shouting.

Other important factors include duration of exposure, susceptibility of an individual to infection and viral load of the transmitter, they said. 

The paper argued: ‘Evidence suggests Sars-CoV-2 may travel more than two metres through activities such as coughing and shouting.

‘Rules on distancing should reflect the multiple factors that affect risk, including ventilation, occupancy, and exposure time.’

The authors called for more work to develop solutions to examine appropriate distances for people in different settings.

Instead of a one-size-fits-all approach to social distancing, there should be ‘graded recommendations’ for different distancing rules in different settings, they argued. 

Pubs, bars and night clubs are the most risky and should have stricter social distancing rules, the paper said.

It did not give an example of a low risk scenario, but said the best conditions would be outdoors, in silence, with few people and face masks.  

The researchers conclude: ‘Physical distancing should be seen as only one part of a wider public health approach to containing the Covid-19 pandemic.

‘It needs to be implemented alongside combined strategies of people-air-surface-space management, including hand hygiene, cleaning, occupancy and indoor space and air managements, and appropriate protective equipment, such as masks, for the setting.’

The paper noted a landmark review commission by the World Health Organization, which supported a one metre or more rule to limit Covid-19 spread. It was heavily based on data from the coronaviruses SARS and MERS, which are related to the virus that causes Covid-19 but arguably different. The study said keeping one metre apart can slash the risk of catching coronavirus by 80 per cent. But halving this gap raised the risk to only 2.6 per cent

The paper noted a landmark review commission by the World Health Organization, which supported a one metre or more rule to limit Covid-19 spread. It was heavily based on data from the coronaviruses SARS and MERS, which are related to the virus that causes Covid-19 but arguably different. The study said keeping one metre apart can slash the risk of catching coronavirus by 80 per cent. But halving this gap raised the risk to only 2.6 per cent 

The two-metre rule in England and Northern Ireland was reduced to 'one metre plus' in July in order to help pubs, restaurants and shops re-open. Pictured: How empty a pub would be with two-metre social distancing

The two-metre rule in England and Northern Ireland was reduced to ‘one metre plus’ in July in order to help pubs, restaurants and shops re-open. Pictured: How empty a pub would be with two-metre social distancing








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

The World Health Organization (WHO) 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.

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

SO, WHAT HAVE THE STUDIES SHOWN?

ONE METRE

Number 10’s chief scientific adviser – Sir Patrick Vallance – has said that the one metre rule is up to 30 times more risky than the two metre rule.

He told MPs earlier this month the risk of spending a minute next to a Covid-19 patient for two minutes was ‘about the same’ as being within a metre of a Covid-19 case for six seconds.

The latest evidence, published in The Lancet, found there was roughly a 2.6 per cent chance of catching the virus when one metre from a Covid patient. But doubling the gap cut the risk to only 1.3 per cent.

However, other scientists have called the data used in the study into question.

Oxford professors Carl Heneghan and Tom Jefferson said the data was ‘poor quality’, while Dr Mike Lonergan at The University of Dundee said: ‘These data give no indication that two metres is better than one metre.’

TWO METRE

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

Professor Robert Dingwall, a member of Nervtag, referred to it as a ‘rule of thumb’ rather than a scientifically proven measure.

Other experts have said the distance may be a non-scientific estimate that just caught on in countries around the world.

IS TWO METRES ENOUGH?

The UK’s coronavirus social distancing limit is four times too short and the gap should be 26 feet, said experts at the Massachusetts Institute of Technology in March.

They found viral droplets expelled in coughs and sneezes can travel in a moist, warm atmosphere at speeds of between 33 and 100ft per second.

This creates a cloud in the atmosphere that can span approximately 23ft to 27ft (seven metres to eight metres) to neighbouring people, the team said.

Another study by scientists in Cyprus, published a fortnight ago, added to the evidence when it found the two-metre rule may not be far enough.

Researchers found even in winds of two miles per hour (mph) – the speed needed for smoke to drift – saliva can travel 18 feet in just five seconds.

And scientists from the universities of California Santa Barbara and Stanford last week said the two metre rule may have to be trebled when winter strikes.

They found droplets that carry SARS-CoV-2 – the coronavirus that causes Covid-19 – can travel up to 20feet (six metres) in cold and humid areas.

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