Respect des distances physiques dans la queue (avec marquage au sol) d'un bureau de poste à Genève en avril 2020.Affiche de l'Office suisse de la santé publique recommandant de « garder ses distances » pendant la pandémie de coronavirus de 2019-2020.Marquages au sol pour favoriser le respect des distances physiques au Dolores Park de San Francisco. Mai 2020.Marquages et séparations de distanciation sociale, Église catholique du Sacré-cœur le 17 juin 2020 à Montreux, Suisse.
La distanciation physique[1],[2], également appelée distanciation sociale[1],[2] ou éloignement sanitaire[2], est une mesure visant à éloigner les individus les uns des autres. C'est l'une des mesures non pharmaceutiques de contrôle des infections prises par les responsables de la santé publique pour arrêter ou ralentir la propagation d'une maladie très contagieuse comme les maladies infectieuses émergentes. L'objectif de la distanciation physique est de réduire la probabilité de contacts entre les personnes porteuses d'une infection et d'autres personnes non infectées, de manière à réduire la transmission de la maladie, la morbidité et la mortalité[3]. C'est un des comportements-barrière qui participe à la réduction des risques sanitaires.
L'éloignement physique est la mesure la plus efficace lorsque l'infection peut être transmise par contacts de gouttelettes (toux ou éternuements) ; par contact physique direct, y compris sexuel ; par contact physique indirect (par exemple en touchant une surface contaminée) ; ou par transmission aérienne (si le micro-organisme peut survivre dans l'air pendant de longues périodes)[4].
L'éloignement physique est moins efficace dans les cas où l'infection est transmise principalement par de l'eau ou des aliments contaminés ou par des vecteurs tels que les moustiques ou autres insectes, et moins fréquemment de personne à personne[5].
Les inconvénients de la distanciation physique peuvent inclure la solitude, la réduction de la productivité au travail (partiellement compensée par le télétravail et les téléconférences[6]) et la perte d'autres avantages liés aux interactions humaines. Dans les endroits où l'accès à la technologie est réduit, elle peut également rendre plus difficile le suivi de la santé d'une population.
Histoire
En , lors de la pandémie de grippe espagnole, Max C. Starkloff, médecin responsable de la santé de la ville de Saint-Louis dans le Missouri (États-Unis), met notamment en place une distanciation physique en interdisant les rassemblements de plus de 20 personnes. Les décisions de Starkloff permettent de limiter les effets de la pandémie dans la ville et sont considérées comme la première mise en place d'une distanciation physique à l'époque moderne[7],[8].
Le terme est importé par l'Organisation mondiale de la santé dès 2006, et on en trouve une description sous la plume de Charles Gilbert (L’Express du 2 mars 2006) dans un article intitulé "On ne se touche plus”[9] :
« Selon les experts de l’Organisation mondiale de la santé (OMS), la maladie pourrait toucher plus de 1 milliard d’individus dans le monde et laisser les autorités démunies devant l’épidémie : les stocks de médicaments antiviraux sont notoirement insuffisants dans tous les pays et les premiers vaccins contre la nouvelle maladie seront prêts, au mieux, dans quatre à six mois. La seule arme immédiatement disponible pour ralentir ce fléau s’appelle la “distanciation sociale”. Cette expression définit, dans les codes de procédures d’urgence recommandées par l’OMS, toutes les mesures de quarantaine visant à diminuer au maximum les contacts physiques entre les individus: interdiction des manifestations et des réunions publiques, restriction des déplacements dans les transports en commun, port du masque obligatoire… »
L'année 2009 est une année de diffusion de l'expression en lien avec la pandémie de Grippe A (H1N1) de 2009. À cette occasion, l'Organisation mondiale de la santé a recommandé des mesures de distanciation physique et d'hygiène personnelle[10]. Le 18 septembre 2009 (21h46), l'agence Xinhua fait passer un communiqué intitulé “la production de vaccins inférieure aux prévisions” et conclut :
« L’agence onusienne recommande également diverses mesures préventives et de traitement, y compris les antiviraux et d’autres médicaments, la distanciation physique et l’hygiène personnelle[9]. »
Pour illustrer ce phénomène, on retient que l’agence News Press publie à son tour, mais le 2 juin 2017 (12h15), un communiqué qui n’est guère repris intitulé : « La peur joue un rôle déterminant dans une épidémie d’Ebola ». Il y est indiqué que l’agence sanitaire, l’OMS, préconise :
« Une distanciation physique, accompagnée d’un suivi sanitaire. Les personnes ayant été en contact avec un malade sont surveillées pendant 21 jours et il leur est demandé de rester à leur domicile pour faciliter cette surveillance et éviter d’exposer d’autres personnes[9]. »
Le 20 mars 2020, l’OMS a indiqué dans un bulletin d’information[13] qu’il convenait de privilégier désormais l'expression « distanciation physique » à celle de « distanciation sociale » pour mieux décrire la nécessité de maintenir un espace entre les personnes pour contenir la propagation d’une épidémie comme celle actuelle de la COVID-19. Selon son épidémiologiste Maria Van Kerkhove, le confinement physique ne doit pas signifier l'isolement social des proches ou de la famille, car il est nécessaire de préserver une bonne santé mentale qui est aussi importante que la santé physique pour surmonter la crise sanitaire. Nous pouvons ainsi, selon elle, rester connectés de nombreuses manières via internet et les médias sociaux sans être physiquement dans la même pièce ou dans le même espace que les gens[14].
Le , au Japon, le terme sanmitsu(三密?) désignant la distanciation physique a été élu mot de l’année 2020 par la maison d’édition japonaise Jiyūkokuminsha(ja). Le kanji三 (san) désigne le chiffre 3, et le kanji 密 (mitsu), la promiscuité. Il rappelle trois situations à éviter pour freiner la progression de l’épidémie de COVID : les espaces clos, la concentration de personnes dans un même lieu et l’absence de distanciation physique entre ces personnes[15].
Terminologie
Mise en place d'une distanciation physique dans une salle de classe au Rwanda.
Le terme « distanciation physique » reste plus adéquat selon les autorités de France, car il exprime une mise en place de distance de sécurité[17],[18],[19].
En , le terme « distanciation sociale » fait son entrée dans Le Petit Robert 2021[20].
La distanciation sociale est un enjeu politique qui fait écho à la notion française de « fracture sociale »[21].
Normes proposées ou établies
L'UNE (Spanish Association for Standardisation-UNE) en collaboration avec l'institut pour la qualité touristique espagnole[22] a publié une série de Spécifications UNE de type guide-ânes et recommandations pour réduire le risque de propagation du coronavirus SARS-CoV-2 — le virus de la maladie à coronavirus — dans le secteur du tourisme[23].
Ces spécifications de la famille UNE-0066 sont publiées gratuitement, mais en échange d'un enregistrement. Elles incluent les visites de plages, vignobles[24], organisations industrielles, culturelles et de sites historiques, société de transport par autocar de tourisme, société de location de véhicules, transport par câble et société de transport d'eau/par eau[25], équipements sportifs nautiques et activités nautiques, loisirs nocturnes, espaces naturels protégés, parcs de loisir et d'amusement, tourisme MICE[26]et espaces publics uniques[27],[23].
Exemples de distanciation physique
Huit manières alternatives de saluer sans contact[28] : agiter la main ; placer sa main sur son cœur ; Namasté ; lever les pouces ; lever les sourcils ; hocher du menton ; hocher de la tête ; hausser les épaules.Manifestation en faveur de l'Affaire du siècle, dans le respect de la distanciation physique, le 14 janvier 2021 à Paris.
Voici quelques exemples de distanciation physique (ou dite sociale) utilisée pour limiter la propagation de maladies contagieuses[29],[30] :
Une mesure essentielle a été la fermeture de lieux de rassemblement de masse, dont :
la fermeture d'écoles (proactive ou réactive)[31] ;
la fermeture de lieux de travail non indispensables[32], y compris la fermeture d'entreprises et de services sociaux non essentiels (non essentiel signifie les installations qui ne maintiennent pas de fonctions primaires dans la communauté, par opposition aux services essentiels[33]) ;
la fermeture de lieux de culte. De nombreux foyers de contamination de COVID-19 ont été créés par des rassemblements religieux ; le 7 avril, l'OMS a recommandé à toutes les communautés et autorités religieuses d'« éviter les grands rassemblements et organiser les rituels et les activités religieuses à distance/virtuellement, selon le cas et dans la mesure du possible ; de veiller à ce que toute décision d’organiser des rassemblements à des fins de prière ou d’éducation ou des rencontres sociales s’appuie sur une évaluation solide des risques et soit conforme aux orientations des autorités nationales et locales ; et lorsqu’ils ont lieu, veiller à ce que les rassemblements, cérémonies et rituels religieux se déroulent dans des conditions sûres »[34] ;
l'annulation de rassemblements de masse tels que les manifestations sportives, les films et les spectacles musicaux[35] ;
les mesures d'autoprotection telles que la limitation des contacts face à face (voir paragraphe suivant), la conduite des affaires par téléphone ou en ligne, l'évitement des lieux publics et la réduction des déplacements non essentiels[38],[39] ;
Puis, en juin 2020, un article de Derek Chu et al., publié dans The Lancet, produit à partir de 172 études observationnelles et d'une compilation des preuves issues de 44 études comparatives sur le SRAS, le syndrome respiratoire du Moyen-Orient (MERS), COVID-19 et les bêtacoronavirus a montré que le risque d’infection diminue de 82 % avec une distance physique de 1 m dans les contextes de soins de santé et dans les rassemblements de personnes, et pour chaque mètre supplémentaire de distanciation, la protection relative a plus que doublé (en se basant sur les données disponibles jusqu'à 3 m)[42].
Ces preuves, compilées par le groupe canadien SURGE (Systematic Urgent Review Group Effort) avec Cochrane Canada, chargé de l'examen critique systématique des études existantes sur la COVID-19, ont permis d’étayer les recommandations faites sur la distance physique. Elles montrent qu’une réduction très importante des risques résulte de cette distance physique, mais que « la règle de la distance de 1 à 2 m dans la plupart des directives hospitalières est basée sur des résultats obsolètes des années 1940, avec des études de 2020 montrant que les grosses gouttelettes peuvent se déplacer jusqu'à 8 m »[43]. Une étude a trouvé un virus viable dans l'air 16 h après l'aérosolisation et le SARS-CoV-2 a montré une plus grande propension à être aéroporté, par rapport au SARS-CoV et MERS-CoV[44]. L'étude de Derek et al. porte aussi sur l'intérêt respectif de divers types de masque[41].
Efficacité, conditions de réussite
Des recherches indiquent que les mesures doivent être appliquées rigoureusement et immédiatement pour être efficaces[45].
Par exemple, lors de la grippe espagnole de 1918, des fermetures d'écoles, des interdictions de rassemblements publics et d'autres interventions de distanciation physique ont été instaurées à Philadelphie et à Saint-Louis (Missouri), mais à Philadelphie, le retard de cinq jours dans le lancement de ces mesures a laissé doubler les taux de transmission de trois à cinq fois, alors qu'une intervention plus immédiate à Saint-Louis, par le biais de Max C. Starkloff, a permis de réduire considérablement la transmission à cet endroit[46] (deux fois moins de cas par nombre d'habitants[8],[47]).
Par ailleurs, la quarantaine de Saint-Louis a permis de réduire la courbe épidémique, en étalant les infections et donc en étalant la prise en charge des malades[48].
Bootsma et Ferguson ont analysé les mesures de distanciation physique dans seize villes américaines pendant l'épidémie de 1918. Ils ont constaté que les interventions limitées dans le temps ne réduisaient que modérément la mortalité totale (peut-être de 10-30 %), et que l'impact était souvent très limité parce que les interventions étaient introduites trop tard et levées trop tôt. Ils ont observé que plusieurs villes ont connu un deuxième pic épidémique après la levée des contrôles de distanciation physique, car les personnes sensibles qui avaient été protégées étaient désormais exposées[49].
Des enjeux sont donc de commencer assez tôt, de ne pas déconfiner trop tôt et d'avoir une communication de crise adaptée aux différents publics, métiers et cultures pour permettre l'adhésion de tous à la distanciation physique, cruciale contre la contagion par des pathogènes aéroportés. Il est à noter que depuis les années 1990, la démocratisation du téléphone et de l'internet (pour ceux qui y ont accès) a fait que le confinement est devenu une distanciation plus physique que physique.
Fermeture d'écoles
Les fermetures d'écoles ont réduit la morbidité due à la grippe asiatique de 90 % lors de l'épidémie de 1957-1958[50], et jusqu'à 50 % dans la lutte contre la grippe aux États-Unis, de 2004 à 2008[51]. De même, les fermetures d'écoles obligatoires et d'autres mesures de distanciation physique ont été associées à une réduction de 29 à 37 % des taux de transmission de la grippe lors de l'épidémie de grippe de 2009 au Mexique[52].
Fermeture de lieux de travail
Des études de modélisation et de simulation basées sur des données américaines suggèrent que si 10 % des lieux de travail touchés sont fermés, le taux global de transmission de l'infection est d'environ 11,9 % et le pic épidémique est légèrement retardé. En revanche, si 33 % des lieux de travail touchés sont fermés, le taux d'infection tombe à 4,9 % et le pic épidémique est retardé d'une semaine[53].
Mise en quarantaine des contacts et des cas suspects
Lors de l'épidémie de SRAS de 2003 à Singapour, quelque 8 000 personnes ont été soumises à une quarantaine obligatoire à domicile et 4 300 autres ont dû s'autosurveiller pour détecter les symptômes et prendre contact quotidiennement par téléphone avec les autorités sanitaires afin de contrôler l'épidémie. Bien que seulement 58 de ces personnes aient finalement reçu un diagnostic de SRAS, les responsables de la santé publique ont estimé que cette mesure a contribué à prévenir la propagation de l'infection[54].
De même, l'auto-isolement volontaire a peut-être contribué à réduire la transmission de la grippe au Texas en 2009[55].
En 1995, un cordon sanitaire a été utilisé pour contrôler une épidémie de virus Ebola à Kikwit, au Zaïre[56],[57],[58]. Le président Mobutu Sese Seko a encerclé la ville avec des troupes et a suspendu tous les vols dans la communauté. À l'intérieur de Kikwit, l'Organisation mondiale de la santé et les équipes médicales du Zaïre ont érigé d'autres cordons sanitaires, isolant les zones d'inhumation et de traitement de la population générale et réussissant à contenir l'infection[59].
Lors de l'épidémie de SRAS de 2003 au Canada, la quarantaine communautaire a été utilisée pour réduire la transmission de la maladie avec un succès modéré[60].
Pendant la pandémie de grippe espagnole de 1918, la ville de Gunnison, au Colorado, s'est isolée pendant deux mois pour éviter l'introduction de l'infection. Toutes les routes ont été barricadées près des limites du comté. Les chefs de train ont averti tous les passagers que s'ils sortaient du train à Gunnison, ils seraient arrêtés et mis en quarantaine pendant cinq jours. Grâce à cette mesure, personne n'est mort de la grippe à Gunnison pendant l'épidémie[61]. Plusieurs autres communautés ont adopté des mesures similaires[62].
Annulation des rassemblements de masse
Les preuves suggérant que les rassemblements de masse augmentent le potentiel de transmission des maladies infectieuses ne sont pas concluantes[63].
Des preuves anecdotiques suggèrent que certains types de rassemblements de masse peuvent être associés à un risque accru de transmission de la grippe, et peuvent également semer de nouvelles souches dans une région, ce qui déclenche la transmission communautaire en cas de pandémie. Pendant la pandémie de grippe de 1918, les défilés militaires de Philadelphie[64] et de Boston[65] ont peut-être été responsables de la propagation de la maladie en mélangeant des marins infectés à des foules de civils.
Cependant, il semble que la restriction des rassemblements de masse, combinée à d'autres interventions de distanciation physique, peut contribuer à réduire la transmission[66].
Restrictions de voyage
Il est peu probable que les restrictions aux frontières et/ou aux voyages intérieurs retardent une épidémie de plus de 2 à 3 semaines si elles ne sont pas mises en œuvre avec une couverture supérieure à 99 %[67].
Le dépistage dans les aéroports s'est révélé inefficace pour prévenir la transmission du virus lors de l'épidémie de SRAS de 2003 au Canada[68] et aux États-Unis[69].
Des contrôles stricts aux frontières entre l'Autriche et l'Empire ottoman, imposé de 1770 à 1871 pour empêcher les personnes infectées par la peste bubonique d'entrer en Autriche, se sont avérés efficaces, car il n'y a pas eu de grandes épidémies de peste sur le territoire autrichien après leur création, alors que l'Empire ottoman a continué à connaître de fréquentes épidémies de peste jusqu'au milieu du XIXe siècle[70].
Une étude de la Northeastern University publiée en mars 2020 a révélé que « les restrictions de voyage à destination et en provenance de la Chine ne font que ralentir la propagation internationale de COVID-19 [lorsqu'elles] sont combinées aux efforts visant à réduire la transmission au niveau communautaire et individuel... Les restrictions de voyage ne sont pas suffisantes à moins que nous les associions à une distanciation sociale »[71]. L'étude a révélé que l'interdiction de voyage à Wuhan n'a fait que retarder de trois à cinq jours la propagation de la maladie dans d'autres parties de la Chine continentale, bien qu'elle ait réduit la propagation des cas internationaux de 80 %. L'une des principales raisons pour lesquelles les restrictions de voyage ont été moins efficaces est que de nombreuses personnes atteintes de COVID-19 ne présentent pas de symptômes au cours des premiers stades de l'infection[72].
des fourmis noires des jardins infectées par le champignon mortel Metarhizyum brunneum diminuent leurs contacts avec la colonie, et les fourmis en bonne santé réduisent leurs interactions sociales, différemment selon leur fonction dans la colonie[74] ;
des langoustes blanches, généralement grégaires, renoncent à partager l'abri d'un individu infecté par le virus mortel PaV1, repérable par certaines substances de son urine[75] ;
parmi les guppys, des poissons d'eau douce généralement grégaires, ceux qui sont particulièrement sensibles au parasitage par des vers invalidants évitent leurs congénères[76] ;
les mandrills, des singes apparentés aux babouins, évitent d'épouiller leurs congénères les plus infectés par des vers intestinaux sauf s'il s'agit de parents proches[78].
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People socially distancing while queuing to enter a supermarket in London during the COVID-19 pandemic Without social distancing and other pandemic containment measures, pathogens can spread exponentially.[1] This graphic shows how early adoption of containment measures tends to protect wider swaths of the population.
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 larger groups.[6][7]
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 other public health recommendations, such as good respiratory hygiene, use of face masks when necessary, 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 have been 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.[citation needed] COVID-19 is much more likely to spread over short distances than long ones. COVID-19 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 2003.[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]
The American Centers for Disease Control and Prevention (CDC) have described social distancing as a set of "methods for reducing frequency and closeness of contact between people in order to decrease the risk of transmission of disease".[10] During the 2009 swine flu pandemic the WHO described social distancing as "keeping at least an arm's length distance from others, [and] minimizing gatherings".[8] During the COVID-19 pandemic, the CDC defined social distancing as "remaining out of congregate settings, avoiding mass gatherings, and maintaining distance (approximately six feet or two meters) from others when possible".[6][7]
Social distancing, combined with the use of face masks, good respiratory hygiene and hand washing, is considered the most feasible way to reduce or delay a pandemic.[8][18]
Measures
Social distancing helps prevent a sharp peak of infections ("flattens the epidemic curve") to help healthcare services deal with demand, and extends time for healthcare services to be increased and improved.[19][20][21][22]
Several social distancing measures are used to control the spread of contagious illnesses. Research indicates that measures must be applied rigorously and immediately in order to be effective.[23]
Avoiding physical contact
Social distancing includes eliminating the physical contact that occurs with the typical handshake, hug, or hongi; this New Zealand illustration offers eight alternatives.
Keeping a set physical distance from each other and avoiding hugs and gestures that involve direct physical contact, reduce the risk of becoming infected during outbreaks of infectious respiratory diseases (for example, flu pandemics and the COVID-19 pandemic of 2020.)[6][24] These distances of separation, in addition to personal hygiene measures, are also recommended at places of work.[25] Where possible, remote work may be encouraged.[9][26]
The WHO's one-metre recommendation stems from research into droplet-based transmission of tuberculosis by William F. Wells, which had found that droplets produced by exhalation, coughs, or sneezes landed an average of 3 ft (0.9 m) from where they were expelled.[28][29][30]Quartz speculated that the U.S. CDC's adoption of 6 ft (1.8 m) may have stemmed from a study of SARS transmission on an airplane, published in The New England Journal of Medicine. When contacted, however, the CDC did not provide any specific information.[31]
Some have suggested that distances greater than 1–2 m (3.3–6.6 ft) should be observed.[32][33][34][35][36][37] One minute of loud speaking can produce oral droplets with a load of 7 million SARS-CoV-2 virus per milliliter that can remain for more than eight minutes,[38] a time-period during which many people could enter or remain in the area. A sneeze can distribute such droplets as far as 7 m (23 ft) or 8 m (26 ft).[39] Social distancing is less effective than face masks at reducing the spread of COVID-19.[40]
Various alternatives have been proposed for the tradition of handshaking. The gesture of namaste, placing one's palms together, fingers pointing upwards, drawing the hands to the heart, is one non-touch alternative. During the COVID-19 pandemic in the United Kingdom, this gesture was used by Prince Charles upon greeting reception guests, and has been recommended by the Director-General of the WHO, Dr. Tedros Adhanom Ghebreyesus, and Israeli Prime Minister Benjamin Netanyahu.[41] Other alternatives include the popular thumbs up gesture, the wave, the shaka (or "hang loose") sign, and placing a palm on one's heart, as practiced in parts of Iran.[41]
Muslims in Indonesia pray in congregation while imposing to strict physical-distancing protocols during the COVID-19 pandemic. During the pandemic, Mosques in Indonesia has also removed the indoor rugs and has ordered worshipers to bring their own personal prayer rugs to prevent the spreading of the virus. Some mosques which are located in the most infected regions even are ordered to be closed for worship
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.
Floor markings can help people maintain distance in public places, especially when queueing.
Urinals adjusted in a way close contacts are less likely
School closures
Swine flu cases per week in the United Kingdom in 2009; schools typically close for summer in mid-July and re-open in early September.[42]
Mathematical modeling has shown that transmission of an outbreak may be delayed by closing schools. However, effectiveness depends on the contacts children maintain outside of school. Often, one parent has to take time off work, and prolonged closures may be required. These factors could result in social and economic disruption.[43][44]
Workplace closures
Modeling and simulation studies based on U.S. data suggest that if 10% of affected workplaces are closed, the overall infection transmission rate is around 11.9% and the epidemic peak time is slightly delayed. In contrast, if 33% of affected workplaces are closed, the attack rate decreases to 4.9%, and the peak time is delayed by one week.[45][46] Workplace closures include closure of "non-essential" businesses and social services ("non-essential" means those facilities that do not maintain primary functions in the community, as opposed to essential services).[47][26]
Canceling mass gatherings
VE Day celebrations in 2020 took place under lockdown; here a socially distanced street party is taking place on Hallfield Estate, Wetherby.
Cancellation of mass gatherings includes sports events, films or musical shows.[48] Evidence published in 2006 suggesting that mass gatherings increase the potential for infectious disease transmission is inconclusive.[49]Anecdotal evidence suggests certain types of mass gatherings may be associated with increased risk of influenza transmission, and may also "seed" new strains into an area, instigating community transmission in a pandemic. During the 1918 influenza pandemic, military parades in Philadelphia[50] and Boston[51] may have been responsible for spreading the disease by mixing infected sailors with crowds of civilians. Restricting mass gatherings, in combination with other social distancing interventions, may help reduce transmission.[26][52] A 2020 peer-reviewed study in the British Medical Journal (The BMJ) also suggested it as one of the key components of an effective strategy in reducing the burden of COVID-19.[22]
Travel restrictions
Border restrictions or internal travel restrictions are unlikely to delay an epidemic by more than two to three weeks unless implemented with over 99% coverage.[53] Airport screening was found to be ineffective in preventing viral transmission during the 2003 SARS outbreak in Canada[54] and the U.S.[55] Strict border controls between Austria and the Ottoman Empire, imposed from 1770 until 1871 to prevent persons infected with the bubonic plague from entering Austria, were reportedly effective, as there were no major outbreaks of plague in Austrian territory after they were established, whereas the Ottoman Empire continued to suffer frequent epidemics of plague until the mid-nineteenth century.[56][57]
A Northeastern University study published in March 2020 found that "travel restrictions to and from China only slow down the international spread of COVID-19 [when] combined with efforts to reduce transmission on a community and an individual level. ... Travel restrictions aren't enough unless we couple it with social distancing."[58] The study found that the travel ban in Wuhan delayed the spread of the disease to other parts of mainland China only by three to five days, although it did reduce the spread of international cases by as much as 80 percent.[59]
Shielding
Shielding measures for individuals include limiting face-to-face contacts, conducting business by phone or online, avoiding public places and reducing unnecessary travel.[60][61][62]
During the COVID-19 pandemic in the United Kingdom, shielding referred to special advisory measures put in place by the UK Government to protect those at the highest risk of serious illness from the disease. This included those with weakened immune systems (such as organ transplant recipients), as well as those with certain medical conditions such as cystic fibrosis or severe asthma. Until 1 June 2020, those shielding were strongly advised not to leave home for any reason at all, including essential travel, and to maintain a 2 m (6.6 ft) distance from anyone else in their household. Supermarkets quickly made priority grocery delivery slots available to those shielding, and the Government arranged for food boxes to be sent to those shielding who needed additional assistance, for example elderly people shielding on their own. This was gradually relaxed from June to allow shielders to spend more time outside, before being suspended indefinitely from 1 August.[citation needed]
During the 2003 SARS outbreak in Singapore, approximately 8000 people were subjected to mandatory home quarantine and an additional 4300 were required to self-monitor for symptoms and make daily telephone contact with health authorities as a means of controlling the epidemic. Although only 58 of these individuals were eventually diagnosed with SARS, public health officials were satisfied that this measure assisted in preventing further spread of the infection.[63] Voluntary self-isolation may have helped reduce transmission of influenza in Texas in 2009.[64] Short and long-term negative psychological effects have been reported.[11]
The objective of stay-at-home orders is to reduce day-to-day contact between people and thereby reduce the spread of infection[65] During the COVID-19 pandemic, early and aggressive implementation of stay-at-home orders was effective in "flattening the curve" and provided the much needed time for healthcare systems to increase their capacity while reducing the number of peak cases during the initial wave of illness.[26] It is important for public health authorities to follow disease trends closely to re-implement appropriate social distancing policies, including stay-at-home orders, if secondary COVID-19 waves appear.[26]
In 1995, a cordon sanitaire was used to control an outbreak of Ebola virus disease in Kikwit, Zaire.[66][67][68] President Mobutu Sese Seko surrounded the town with troops and suspended all flights into the community. Inside Kikwit, the World Health Organization and Zaire's medical teams erected further cordons sanitaires, isolating burial and treatment zones from the general population and successfully containing the infection.[69]
During the 1918 influenza epidemic, the town of Gunnison, Colorado, isolated itself for two months to prevent an introduction of the infection. Highways were barricaded and arriving train passengers were quarantined for five days. As a result of the isolation, no one died of influenza in Gunnison during the epidemic.[70] Several other communities adopted similar measures.[71]
Other measures
Other measures include shutting down or limiting mass transit[72] and closure of sport facilities (community swimming pools, youth clubs, gymnasiums).[73] Due to the highly interconnected nature of modern transportation hubs, a highly contagious illness can achieve rapid geographic spread if appropriate mitigation measures are not taken early.[26] Consequently, highly coordinated efforts must be put into place early during an outbreak to proactively monitor, detect, and isolate any potentially infectious individuals.[26] If community spread is present, more aggressive measures may be required, up to and including complete cessation of travel in/out of a specific geographic area.[26]
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]
History
Leper colonies and lazarettos were established as a means of preventing the spread of leprosy and other contagious diseases through social distancing,[75] until transmission was understood and effective treatments invented.
Two lepers denied entrance to town. Woodcut by Vincent of Beauvais, 14th century
New York City parks and playgrounds were closed during a 1916 polio epidemic.[76]
Passenger without mask being refused boarding of a streetcar amid 1918 flu pandemic. (Seattle, Washington, 1918)
1916 New York City polio epidemic
During the 1916 New York City polio epidemic, when there were more than 27,000 cases and more than 6,000 deaths due to polio in the United States, with more than 2,000 deaths in New York City alone, movie theaters were closed, meetings were cancelled, public gatherings were almost non-existent, and children were warned not to drink from water fountains, and told to avoid amusement parks, swimming pools and beaches.[77][78]
Influenza, 1918 to present
An article naming wealthy socialites for violating city law banning public gatherings, Chicago Tribune, October 19, 1918. Named violators include Joan Pinkerton Chalmers, daughter of Pinkertons private police founder Allan Pinkerton.[79]
During the influenza pandemic of 1918, Philadelphia saw its first cases of influenza on 17 September.[80][15] The city continued with its planned parade and gathering of more than 200000 people on 28 September and over the subsequent three days, the city's 31 hospitals became fully occupied. During the week ending 16 October, over 4500 people died.[50][81] Social distancing measures were introduced on 3October, on the orders of St. Louis physician Max C. Starkloff,[82] more than two weeks after the first case.[15] Unlike Philadelphia, St. Louis experienced its first cases of influenza on 5October and the city took two days to implement several social distancing measures,[15] including closing schools, theatres, and other places where people get together. It banned public gatherings, including funerals. The actions slowed the spread of influenza in St. Louis and a spike in cases and deaths, as had happened in Philadelphia, did not occur.[83] The final death rate in St. Louis increased following a second wave of cases, but remained overall less than in other cities.[84] Bootsma and Ferguson analyzed social distancing interventions in sixteen U.S. cities during the 1918 epidemic and found that time-limited interventions reduced total mortality only moderately (perhaps 10–30%), and that the impact was often very limited because the interventions were introduced too late and lifted too early. It was observed that several cities experienced a second epidemic peak after social distancing controls were lifted, because susceptible individuals who had been protected were now exposed.[85]
School closures were shown to reduce morbidity from the Asian flu by 90% during the 1957–1958 pandemic,[86] and up to 50% in controlling influenza in the U.S., 2004–2008.[87] Similarly, mandatory school closures and other social distancing measures were associated with a 29% to 37% reduction in influenza transmission rates during the 2009 flu epidemic in Mexico.[88]
The 2009 swine flu pandemic caused social distancing to rise in popularity, most notably in Mexico, with the country's Ministry of Health advising people to avoid handshakes and kissing as ways of greeting people.[89] A mandatory nationwide school closure enacted in Mexico, which lasted for 18 days from late April 2009 to early May 2009, was a form of social distancing aimed at reducing the transmission of Swine flu.[90] A study from 2011 found the mandatory nationwide school closure and other forms of social distancing in Mexico were effective at reducing influenza transmission rates.[90]
During the swine flu outbreak in 2009 in the UK, in an article titled "Closure of schools during an influenza pandemic" published in The Lancet Infectious Diseases, a group of epidemiologists endorsed the closure of schools to interrupt the course of the infection, slow the further spread and buy time to research and produce a vaccine.[91] Having studied previous influenza pandemics including the 1918 flu pandemic, the influenza pandemic of 1957 and the 1968 flu pandemic, they reported on the economic and workforce effect school closure would have, particularly with a large percentage of doctors and nurses being women, of whom half had children under the age of 16. They also looked at the dynamics of the spread of influenza in France during French school holidays and noted that cases of flu dropped when schools closed and re-emerged when they re-opened. They noted that when teachers in Israel went on strike during the flu season of 1999–2000, visits to doctors and the number of respiratory infections dropped by more than a fifth and more than two fifths respectively.[92]
SARS 2003
During the SARS outbreak of 2003, social distancing measures were implemented, such as banning large gatherings, closing schools and theaters, and other public places, supplemented public health measures such as finding and isolating affected people, quarantining their close contacts, and infection control procedures. This was combined with the wearing of masks for certain people.[93] During this time in Canada, "community quarantine" was used to reduce transmission of the disease with moderate success.[94]
For those in the general public wishing to wear N95 respirators, properly wearing a N95 was noted to be difficult, but the tendency for people to distance themselves from those wearing masks was said to compliment the six-foot social distancing rules at the time.[95]
This section needs to be updated. Please help update this article to reflect recent events or newly available information.(March 2021)
Simulations comparing rate of spread of infection, and number of deaths due to overrun of hospital capacity, when social interactions are "normal" (left, 200 people moving freely) and "distanced" (right, 25 people moving freely). Green = Healthy, uninfected individuals Red = Infected individuals Blue = Recovered individual Black = Dead individuals [96]
During the COVID-19 pandemic, social distancing and related measures are emphasized by several governments as alternatives to an enforced quarantine of heavily affected areas.[26] According to UNESCO monitoring, more than a hundred countries have implemented nationwide school closures in response to COVID-19, impacting over half the world's student population.[97] In the United Kingdom, the government advised the public to avoid public spaces, and cinemas and theaters voluntarily closed to encourage the government's message.[98]
With many people disbelieving that COVID-19 is any worse than the seasonal flu,[99] it has been difficult to convince the public—particularly youth, and the anti vaxx community to voluntarily adopt social distancing practices.[100][101] In Belgium, media reported a rave was attended by at least 300 before it was broken up by local authorities. In France, teens making nonessential trips are fined up to US$150. Beaches were closed in Florida and Alabama to disperse partygoers during spring break.[102] Weddings were broken up in New Jersey and an 8p.m. curfew was imposed in Newark. New York, New Jersey, Connecticut and Pennsylvania were the first states to adopt coordinated social distancing policies which closed down non-essential businesses and restricted large gatherings. Shelter in place orders in California were extended to the entire state on 19 March. On the same day Texas declared a public disaster and imposed statewide restrictions.[103]
These preventive measures such as social-distancing and self-isolation prompted the widespread closure of primary, secondary, and post-secondary schools in more than 120 countries. As of 23 March 2020, more than 1.2 billion learners were out of school due to school closures in response to COVID-19.[97] Given low rates of COVID-19 symptoms among children, the effectiveness of school closures has been called into question.[104] Even when school closures are temporary, it carries high social and economic costs.[105] However, the significance of children in spreading COVID-19 is unclear.[106][107] While the full impact of school closures during the coronavirus pandemic are not yet known, UNESCO advises that school closures have negative impacts on local economies and on learning outcomes for students.[108]
In early March 2020, the sentiment "Stay Home" was coined by Florian Reifschneider, a German engineer and was quickly echoed by notable celebrities such as Taylor Swift, Ariana Grande[109][110] and Busy Philipps[111] in hopes of reducing and delaying the peak of the outbreak. Facebook, Twitter and Instagram also joined the campaign with similar hashtags, stickers and filters under #staythefhome, #stayhome, #staythefuckhome and began trending across social media.[112][113][114][115] The website claims to have reached about two million people online and says the text has been translated into 17 languages.[115]
There are concerns that social distancing can have adverse affects on participants' mental health.[26][116] It may lead to stress, anxiety, depression or panic, especially for individuals with preexisting conditions such as anxiety disorders, obsessive compulsive disorders, and paranoia.[26][117] Widespread media coverage about a pandemic, its impact on economy, and resulting hardships may create anxiety. Change in daily circumstances and uncertainty about the future may add onto the mental stress of being away from other people.[26][118]
Psychologist Lennis Echterling noted that, in such social distancing situations, using technology for "connection with loved ones...is imperative" to combat isolation, for the sake of one's well-being.[119] Social worker Mindy Altschul noted that the concept of "social distancing" ought to be reframed as "physical distancing", so as to emphasize the fact that being physically isolated need not, and should not, result in being socially isolated.[120]
People with autism also suffer impact from social distancing. Adjusting to a new routine can be stressful for everyone within the spectrum but especially for children who have trouble with change.[121][122] Children with autism may not know what is going on or might not be able to express their fears and frustrations.[121] They also may need extra support to understand what's expected of them in some situations.[121][122] The adjustment to a new situation can lead to challenging behavior uncharacteristic of the autistic individual's true character.[122] In some countries and demographics, teenagers and young adults within the autistic spectrum disorder (ASD) receive support services including special education, behavioral therapy, occupational therapy, speech services, and individual aides through school, but this can be a major challenge, particularly since many teenagers with ASD already have social and communication difficulties.[123] Aggressive and self-injurious behaviors may increase during this time of fear and uncertainty.[123]
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.
Theoretical basis
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,[124] 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:[124]
Where the value of can be brought below1 for sufficiently long, containment is achieved, and the number infected should decrease.[125]
For any given period of time, the growth in the number of infections can be modeled as:[126]
where:
is the number of infected individuals after incubation periods (5 days, in the case of COVID-19)
Using COVID-19 as an example, the following table shows the infection spread given:
A: No social distance mitigation
B: 50% reduction in social interaction
C: 75% reduction in social interaction
Number of infections after days for various values of
Time
A
B
C
5 days (1 incubation period)
2.5
1.25
0.625
30 days (6 incubation periods)
406
15
2.5
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%.[127]
^Teh, Benjamin; Olsen, Karen; Black, Jim; Cheng, Allen C.; Aboltins, Craig; Bull, Kirstin; Johnson, Paul D. R.; Grayson, M. Lindsay; Torresi, Joseph (2012) [2011-11-22, 2011-09-26, 29 June 2011]. "Impact of swine influenza and quarantine measures on patients and households during the H1N1/09 pandemic". Scandinavian Journal of Infectious Diseases. 44 (4): 289–296. doi:10.3109/00365548.2011.631572. PMID22106922. S2CID24255689.