What is the science behind social distancing?
Prime Minister Boris Johnson has announced that the two metres rule for social distancing in England is being reduced to "one metre plus". Now the people won't stay two metres far apart from each other to avoid the spread of coronavirus. Why the government has reduced from two metres to "one metre plus"? What is the science behind social distancing?
Several countries are suffering from COVID-19 pandemic. According to WHO, the coronavirus outbreak situation in the world on 24 June, 2020 is 9110186 confirmed cases, 473061 confirmed deaths, and around 216 countries, areas, or territories with the cases.
Various measures are suggested by WHO to protect yourself and others from the spread of coronavirus. In this one measure is about social distancing.
What is social distancing?
To reduce the spread of COVID-19, limit face-to-face contact with others. Social distancing is also known as "physical distancing". According to the CDC, to practice social or physical distancing stay at least 6 feet from other people. Keeping space among each other is one of the best ways to avoid being exposed to the virus and slowing its spread locally and across the country and the world.
From 4 July Britain announced an easing of social distancing rules and reducing the recommended gap from two metres to "one metre plus" in England. The lockdown measures are loosened for the COVID-19 pandemic.
Let us first look at why the guidance has changed?
As the number of new infections is now declining by between 2% and 4% every day so Prime Minister said that the changes are possible. They were looking for the changes because sometimes keeping people two metres apart would make it very tricky for places like restaurants and cafes, to re-open and carry out their business further the Prime Minister told. Before announcing the change about the social distancing the Prime Minister met with scientists and other senior politicians.
What is the view of scientists for social distancing?
According to the infectious disease experts, the closer the people are to someone infected with COVID-19, and the more time the people spend in close quarters, the risk will be higher in spreading the coronavirus from one person to another.
A Professor of Physical Chemistry at Britain's Bristol University, Jonathan Reid told that the simple reality is just a matter of reducing the risk with increased physical distance. The far you stand from someone then the fewer droplets you will be exposed to. He further stated that one metre only prevents the risk of being exposed to the largest droplets; two metres reduces exposures but does not make the risk zero.
In this month, a study is also published in The Lancet that physical distancing of at least one metre lowers the risk of COVID-19 transmission, but that two metre could be more effective.
What is the advice given by the World Health Organisation (WHO)?
According to WHO, maintaining the distance of at least one metre helps to reduce the risk of the transmission of COVID-19 spread in the small droplets that people spray out while coughing, sneezing, and talking. These droplets may contain a virus, and if anyone who will be close will breathe the droplet.
Is social distancing the only factor?
According to Switzerland's health ministry " as per current data, a distance of more than one metre reduces the risk of COVID-19 infection by more than 80% in both healthcare settings and in everyday life". Further, they added that the risk will be higher in those circumstances in which a large number of droplets are expelled mainly while speaking loudly or singing.
The professor of engineering at the Britan's University of Cambridge, Shaun Fitzgerald said that "it is not all about the distance". There are other measures also like the duration of close proximity, the number of people in a given space, the use of face masks, availability of ventilation, and whether the people talk slowly, quietly, or loudly.
Coronavirus Infection spread indoors versus outdoors
According to Dr. Macciochi "In the indoors, the infection seems to be more easily spread as compared to outdoors". Also, certain other factors play an important role like air quality, humidity, weather, and air conditioning.
A study by Japan's National Institute of Infectious Diseases found that chance of transmitting the virus was 19 times higher indoors than outside after looking at 110 cases of COVID-19 and tracing the contacts of those infected.
Other factors also matter like time spends with someone. Dr. Macciochi, broadly says, successful infection = exposure to virus x time.
It is also difficult to say how far coronavirus travel?
According to Dr. Rob White, lecturer in Virology at Imperial College London "The virus spread in droplets is clear and known to everyone". He further stated that these droplets may produce due to speaking or coughing or similar. Also, it is not clear that the virus can spread via aerosols the tiny liquid particles produced when simply breathing". If the virus travels through aerosols it could travel much greater distances. However the far the droplets travel, they will fall at some point. That is why hand washing is also recommended.
Social Distancing in other countries
The social distancing of one metre is recommended in China, Denmark, France, Hong Kong, and Singapore and several people also chose or are required to wear face masks in public places.
Whereas in Australia, Belgium, Greece, Germany, Italy, Spain, and Portugal to curb COVID-19 pandemic people are advised to keep 1.5 metre social distancing. Let us tell you that Switzerland has also reduced the social distancing rule from two metres to 1.5 metre. In the United States, the guidance is six feet or 1.8m.
There are also various other measures recommended by the WHO to curb the spread of the COVID-19 pandemic with the social distancing. WHO has recommended maintaining at least one metre distance between yourself and others. But if more than one could be more effective. Also, we can say that a safe distance in the spread of COVID-19 depends on where you live. There are several factors why social distancing is important including respiratory droplets, viral load, infectious dose, environment, etc.
There are various scenarios and one rule that applies to all the countries is also not possible. Important is to take precautions as recommended by WHO.
Stay Safe, Stay Healthy!