THE TWO METRE RULE, SOCIAL DISTANCING, WHERE DOES IT COME FROM?
Government ministers are considering whether to relax the two metre rule social distancing in workplaces. Clearly, this would make it easier for people to get back to jobs where it is not always feasible to stay apart. But is this safe? Where did this rule come from?
There is a wide variety of recommendations in different countries; clearly the closer you are to someone who is infected, the greater the risk.
The World Health Organisation, however, says that a distance of one metre is safe.
The longer one spends in proximity of an infected person, the more chances you have of catching the virus. The UK government have suggested that where face-to-face contact is essential, this should be kept to 15 minutes or less wherever possible. Spending two seconds one metre apart is as dangerous as spending one minute two metres apart.
Where Does the Two-Metre Rule Herald from?
It would appear that it can be traced to research in the 1930s. Scientists established that droplets of liquid released by coughs or sneezes either evaporate quickly in the air or are dragged by gravity down to the ground. They considered that the majority of these droplets would land within one to two metres.
The greatest risks come from having the virus coughed at you from close range or from touching a surface. However, some researchers are now concerned that the coronavirus is not just carried in droplets. They believe it can be transported through the air in tiny particles. If this is the case, then the flow of wind from someone’s breath could carry the virus over longer distances.
Professor Lydia Bourouiba from the Massachusetts Institute of Technology (MIT) found that using high-speed cameras, a cough projecting miniature specks can go as far as six metres. She believes that this two-metre rule is a false idea of safety.
A study in China carried out in hospitals found traces of coronavirus in Covid-19 wards and intensive care units and estimated that four metres was a better safe distance.
However, the US Centre for Disease Control (CDC) believes that the role of aerosols, small particles in spreading the virus is currently uncertain.
It is still not established whether any virus that spreads further than two metres can be infectious.
Is it Safer to be Outdoors than Indoors?
There is wide agreement that the answer to this is yes and this is why construction is going to be one of the first types of works to be allowed when lockdowns are eased.
Japanese researchers who investigated 110 cases of COVID-19, following up the contacts of the people, found that the odds of infection being passed on were nearly 19 times greater indoors than when outside in the fresh air. They concluded closed environments contribute to secondary transmission of COVID-19 and promote super- spreading events.
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