Social distancing
In public health, social distancing, also called physical distancing,[2][3][4] is a set of non-pharmaceutical interventions or measures intended to prevent the spread of a contagious disease by maintaining a physical distance between people and reducing the number of times people come into close contact with each other.[2][5] It usually involves keeping a certain distance from others (the distance specified differs from country to country and can change with time) and avoiding gathering together in large groups.[6][7]
Not to be confused with social distance or social isolation. For the Lil Baby song, see My Turn (Lil Baby album).
By minimising the probability that a given uninfected person will come into physical contact with an infected person, the disease transmission can be suppressed, resulting in fewer deaths.[2] The measures may be used in combination with others, such as good respiratory hygiene, face masks and hand washing.[8][9] To slow down the spread of infectious diseases and avoid overburdening healthcare systems, particularly during a pandemic, several social-distancing measures are used, including the closing of schools and workplaces, isolation, quarantine, restricting the movement of people and the cancellation of mass gatherings.[5][10] Drawbacks of social distancing can include loneliness, reduced productivity and the loss of other benefits associated with human interaction.[11]
Social distancing measures are most effective when the infectious disease spreads via one or more of the following methods, droplet contact (coughing or sneezing), direct physical contact (including sexual contact), indirect physical contact (such as by touching a contaminated surface), and airborne transmission (if the microorganism can survive in the air for long periods). The measures are less effective when an infection is transmitted primarily via contaminated water or food or by vectors such as mosquitoes or other insects.[12] Authorities have encouraged or mandated social distancing during the COVID-19 pandemic as it is an important method of preventing transmission of COVID-19. COVID-19 is much more likely to spread over short distances than long ones. However, it can spread over distances longer than 2 m (6 ft) in enclosed, poorly ventilated places and with prolonged exposure.[13]
The term "social distancing" was not introduced until the 21st century.[14] Social distancing measures have been successfully implemented in several epidemics. In St. Louis, shortly after the first cases of influenza were detected in the city during the 1918 flu pandemic, authorities implemented school closures, bans on public gatherings and other social-distancing interventions. The influenza fatality rates in St. Louis were much less than in Philadelphia, which had fewer cases of influenza but allowed a mass parade to continue and did not introduce social distancing until more than two weeks after its first cases.[15]
The World Health Organization (WHO) has suggested using the term "physical distancing" instead of "social distancing" because it is physical separation which prevents transmission; people can remain socially connected by meeting outdoors at a safe distance (when there is no stay-at-home order) and by meeting via technology.[2][3][16][17]
In this computer lab, every other workstation has been closed off to increase the distance between people working, and screens between workstations are also in place.
Communicating social distancing public health guidelines
Public health messaging, gaining the public's trust (countering misinformation), ensuring community involvement and two-way exchange of ideas can affect the uptake, adherence, and effectiveness of best-evidence social distancing approach to preventing disease spread.[74] The communication approaches, messaging, and delivery mechanisms need to be flexible so that they can be changed as both the best-evidence social distancing measures change and as the community needs change.[74]
The Lazzaretto of Ancona was constructed in the 18th century on an artificial island to serve as a quarantine station and leprosarium for the port town of Ancona, Italy.
![New York City parks and playgrounds were closed during a 1916 polio epidemic.[76]](http://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Popular_science_monthly_%281872%29_%2814596283227%29.jpg/173px-Popular_science_monthly_%281872%29_%2814596283227%29.jpg)
Passenger without mask being refused boarding of a streetcar amid 1918 flu pandemic. (Seattle, Washington, 1918)
Portrayal in literature
In his 1957 science fiction novel The Naked Sun, Isaac Asimov portrays a planet where people live with social distancing. They are spread out, miles from each other, across a sparsely-populated world. Communication is primarily through technology. A male and a female still need to engage in sex to make a baby, but it is seen as a dangerous, nasty chore. In contrast, when communication is through technology the situation is the reverse: there is no modesty, and casual nudity is frequent. The novel's point of departure is a murder: this seemingly idyllic world, in fact, has serious social problems.
is the number of infected individuals after incubation periods (5 days, in the case of COVID-19)
From the perspective of epidemiology, the basic goal behind social distancing is to decrease the effective reproduction number, or , which in the absence of social distancing would equate to the basic reproduction number, i.e. the average number of secondary infected individuals generated from one primary infected individual in a population where all individuals are equally susceptible to a disease. In a basic model of social distancing,[122] where a proportion of the population engages in social distancing to decrease their interpersonal contacts to a fraction of their normal contacts, the new effective reproduction number is given by:[122]
Where the value of can be brought below 1 for sufficiently long, containment is achieved, and the number infected should decrease.[123]
For any given period of time, the growth in the number of infections can be modeled as:[124]
where:
Using COVID-19 as an example, the following table shows the infection spread given:
![{\displaystyle R=[1-(1-a^{2})f]R_{0}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/94c687110c77a2fe49b9f726d449812b8a517df4)
Effectiveness
An empirical study published in July 2020 in The BMJ (British Medical Journal) analyzed data from 149 countries, and reported an average of 13% reduction in COVID-19 incidence after the implementation of social distancing policies.[22] Another study found that four social distancing interventions combined resulted in a reduction of the infection rate from 66% to less than 1%.[125]