What is the purpose of social distancing?
Text updated on 2020-04-29
The virus is spread through contact: keeping distance from others is an easy and effective way to prevent it. In the absence of medication, this is an essential means.
Social distancing refers to a set of measures aimed at keeping individuals away from each other in order to stop or slow the spread of a highly contagious disease such as COVID-19. The following behaviours are part of social distancing: avoiding gatherings, avoiding close contact with other people, and keeping a minimum physical distance between individuals. Social distancing helps to both avoid catching the virus and avoid infecting others.
SARS-CoV-2 was found within a 4-meter perimeter in the vicinity of COVID-19 patients. Maintaining a sufficient distance (1-3 m) between individuals makes it possible to reduce the average number of newly infected people (this is the virus reproduction number, R0) and, thus, to slow down the progression of the virus and the epidemic within a population.
Social distancing, combined with the wearing of masks, is important so as not to saturate our healthcare systems as the number of resuscitation beds for patients in a serious condition is limited. The goal is to reduce the total number of victims of COVID-19.
Social distancing and hygiene measures are all the more critical in large cities where density affects the rate of attack of the epidemic according to a law of scale: the larger and denser the city, the faster a disease spreads between individuals.
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One study shows that COVID-19 spreads much faster in cities with higher population densities.Berman, M. G., Bettencourt, L. M., & Stier, A. J. (2020). COVID-19 attack rate increases with city size. MedRxiv.
Measuring the spread of the virus in a hospital in China reveals that the virus is found within 4 meters of COVID-19 patients.Guo, Z. D., Wang, Z. Y., Zhang, S. F., Li, X., Li, L., Li, C., ... & Zhang, M. Y. (2020). Aerosol and surface distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards, Wuhan, China, 2020. Emerging infectious diseases, 26(7).
A retrospective study conducted between January-February 2020 in Shenzhen, China, shows that people who indicated "often" for their frequency of contact with other people caught more COVID-19 than people who indicated "moderate".Bi, Q., Wu, Y., Mei, S., Ye, C., Zou, X., Zhang, Z., ... & Gao, W. (2020). Epidemiology and Transmission of COVID-19 in Shenzhen China: Analysis of 391 cases and 1,286 of their close contacts. MedRxiv.