Explainer: A meter or two? How social distancing affects the risk of COVID-19

LONDON (Reuters) – Britain announced on Tuesday a relaxation of social distancing rules from July 4, reducing the recommended gap from 2 meters to “1 meter more” in England as it further loosened blockade measures destined to stop the pandemic of COVID-19.

FILE PHOTO: A social distancing sign is displayed in a flower shop after its reopening, amid the outbreak of coronavirus disease (COVID-19), in Llandudno, Wales, Great Britain, June 22, 2020. REUTERS / Carl Recine / File Photo

What do scientists say?

Infectious disease experts say the closer people are to someone infected with COVID-19, and the longer people spend indoors, the greater the risk that the coronavirus will spread from person to person.

Beyond that simple reality, “it is just a matter of reducing risk with greater physical distance,” said Jonathan Reid, professor of physical chemistry at the British University of Bristol.

“The farther you get away from someone, the fewer drops you will be exposed to. One meter only prevents you from exposing yourself to the larger drops; two meters reduces your exposure, but it doesn’t do zero risk.”

A study in The Lancet this month found that physical distancing of at least 1m decreases the risk of COVID-19 transmission, but that 2m could be more effective.


The WHO says keeping a distance of at least a meter helps reduce the risk of the coronavirus spreading in the tiny droplets of liquid that people spray when coughing, sneezing and talking.

These drops can contain the virus and “if you are too close, you can breathe in the drops,” says the WHO.


The Swiss Ministry of Health says that “according to current data, a distance of more than one meter reduces the risk of COVID-19 infection by more than 80% both in medical care (settings) and in everyday life” .

However, he added that the risk is higher “in circumstances where a particularly large number of drops are expelled, such as when singing or speaking aloud.”

Shaun Fitzgerald, a professor of engineering at Cambridge University in Britain, said the key point is that “it’s not just about distance.”

“There are other mitigation measures,” he said, including the duration of proximity, the number of people in a given space, the use of face masks, the availability of ventilation, and whether people speak quietly or shout loudly.


China, Denmark, France, Hong Kong, and Singapore recommend 1-meter social distancing, and many people also choose to wear, or are required to, wear face masks in public spaces.

Australia, Belgium, Greece, Germany, Italy, Spain and Portugal advise people to stay 1.5 meters away. Switzerland this week also reduced the required distance to 1.5m from 2m.

The orientation in the United States is six feet, or 1.8 m.

Additional reports from John Miller in Zurich, Mark Heinrich edition

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