Non-pharmaceutical intervention (epidemiology): Difference between revisions

{{About|the specific use of the term in [[epidemiology]]|the general concept|Non-pharmaceuticalpharmacological intervention}}

In [[epidemiology]], a '''non-pharmaceuticalpharmacological intervention''' (NPI) is any method used to reduce the spread of an [[epidemic]] disease without requiring [[Medication|pharmaceuticalpharmacological drug]] treatments. Examples of non-pharmaceuticalpharmacological interventions that reduce the spread of infectious diseases include [[Face masks during the COVID-19 pandemic|wearing a face mask]] and [[Quarantine|staying away from sick people]].<ref name="auto">{{Citation |last=von Csefalvay |first=Chris |title=Modeling the control of infectious disease |date=2023 |url=https://linkinghub.elsevier.com/retrieve/pii/B9780323953894000153 |work=Computational Modeling of Infectious Disease |pages=173–215 |access-date=2023-03-05 |publisher=Elsevier |language=en |doi=10.1016/b978-0-32-395389-4.00015-3 |isbn=978-0-323-95389-4}}</ref>

The [[US Centers for Disease Control and Prevention]] (CDC) points to personal, community, and environmental interventions.<ref>{{Cite web|date=2019-06-11|title=Nonpharmaceutical Interventions (NPIs) {{!}} CDC|url=https://www.cdc.gov/nonpharmaceutical-interventions/index.html|access-date=2020-04-16|website=www.cdc.gov|language=en-us}}</ref> NPIs have been recommended for pandemic influenza at both local<ref name=":1">{{cite journal | vauthors = Bell D, Nicoll A, Fukuda K, Horby P, Monto A, Hayden F, Wylks C, Sanders L, van Tam J | display-authors = 6 | title = Non-pharmaceutical interventions for pandemic influenza, national and community measures | journal = Emerging Infectious Diseases | volume = 12 | issue = 1 | pages = 88–94 | date = January 2006 | pmid = 16494723 | pmc = 3291415 | doi = 10.3201/eid1201.051371 }}</ref> and global levels,<ref>{{cite journal | vauthors = Bell D, Nicoll A, Fukuda K, Horby P, Monto A, Hayden F, Wylks C, Sanders L, Van Tam J | display-authors = 6 | title = Non-pharmaceutical interventions for pandemic influenza, international measures | journal = Emerging Infectious Diseases | volume = 12 | issue = 1 | pages = 81–7 | date = January 2006 | pmid = 16494722 | pmc = 3291414 | doi = 10.3201/eid1201.051370 }}</ref> and studied at large scale during the [[2009 swine flu pandemic]]<ref>{{cite journal | vauthors = Mitchell T, Dee DL, Phares CR, Lipman HB, Gould LH, Kutty P, Desai M, Guh A, Iuliano AD, Silverman P, Siebold J, Armstrong GL, Swerdlow DL, Massoudi MS, Fishbein DB | display-authors = 6 | title = Non-pharmaceutical interventions during an outbreak of 2009 pandemic influenza A (H1N1) virus infection at a large public university, April-May 2009 | journal = Clinical Infectious Diseases | volume = 52 Suppl 1 | issue = suppl_1 | pages = S138-45 | date = January 2011 | pmid = 21342886 | doi = 10.1093/cid/ciq056 | url = https://academic.oup.com/cid/article/52/suppl_1/S138/501065 | doi-access = free }}</ref> and the [[COVID-19 pandemic]].<ref>{{cite journal | vauthors = Imai N, Gaythorpe KA, Abbott S, Bhatia S, van Elsland S, Prem K, Liu Y, Ferguson NM | display-authors = 6 | title = Adoption and impact of non-pharmaceutical interventions for COVID-19 | journal = Wellcome Open Research | volume = 5 | pages = 59 | date = 2020-04-02 | pmid = 32529040 | pmc = 7255913 | doi = 10.12688/wellcomeopenres.15808.1 | doi-access = free }}</ref><ref>{{Cite web|title=Report 9 - Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand|url=http://www.imperial.ac.uk/medicine/departments/school-public-health/infectious-disease-epidemiology/mrc-global-infectious-disease-analysis/covid-19/report-9-impact-of-npis-on-covid-19/|access-date=2020-04-16|website=Imperial College London|language=en-GB}}</ref><ref name=autogenerated2>{{Cite journal|url=https://doi.org/10.1016/j.jobb.2021.08.003|doi=10.1016/j.jobb.2021.08.003|title=A solution scan of societal options to reduce transmission and spread of respiratory viruses: SARS-CoV-2 as a case study|year=2021|last1=Sutherland|first1=William J.|last2=Taylor|first2=Nigel G.|last3=Aldridge|first3=David C.|last4=Martin|first4=Philip|last5=Rhodes|first5=Catherine|last6=Shackelford|first6=Gorm|last7=Beard|first7=Simon|last8=Belfield|first8=Haydn|last9=Bladon|first9=Andrew J.|last10=Brick|first10=Cameron|last11=Christie|first11=Alec P.|last12=Dobson|first12=Andrew P.|last13=Downey|first13=Harriet|last14=Hood|first14=Amelia S.C.|last15=Hua|first15=Fangyuan|last16=Hughes|first16=Alice C.|last17=Jarvis|first17=Rebecca M.|last18=MacFarlane|first18=Douglas|last19=Morgan|first19=William H.|last20=Mupepele|first20=Anne-Christine|last21=Marciniak|first21=Stefan J.|last22=Nelson|first22=Cassidy|last23=ó Héigeartaigh|first23=Seán|last24=Rios Rojas|first24=Clarissa|last25=Sainsbury|first25=Katherine A.|last26=Smith|first26=Rebecca K.|last27=Sundaram|first27=Lalitha S.|last28=Thornton|first28=Ann|last29=Watkins|first29=John|last30=White|first30=Thomas B.|journal=Journal of Biosafety and Biosecurity|volume=3|issue=2|pages=84–90|pmid=34541465|pmc=8440234|display-authors=1}}</ref> NPIs are a set of measures that can be utilizedused at any time, and are used in the period between the emergence of an epidemic disease and the deployment of an effective vaccine.<ref name=":0">{{Cite book |url=https://apps.who.int/iris/bitstream/handle/10665/329438/9789241516839-eng.pdf|title=Non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic influenza|publisher=[[World Health Organization]]|year=2019|isbn=978-92-4-151683-9|access-date=2020-11-25|archive-url=https://web.archive.org/web/20201118063803/https://apps.who.int/iris/bitstream/handle/10665/329438/9789241516839-eng.pdf|archive-date=2020-11-18|url-status=live}}</ref>

Choosing to stay home to prevent the spread of symptoms of a potential sickness, covering coughs and sneezes, and washing one's hands on a regular basisregularly, are all examples of non-pharmaceuticalpharmacological interventions.<ref name="cdc.gov">{{Cite web|url=https://www.cdc.gov/nonpharmaceutical-interventions/personal/index.html|title = Personal NPIs: Everyday Preventive Actions &#124; Nonpharmaceutical Interventions &#124; CDC|date = 26 August 2019}}</ref> Another example wouldis includewhen administrators of schools, workplaces, community areas, etc., takingtake proper preventive actionactions and remindingremind people to take precautionprecautions when need be in order to avoid the spread of disease.<ref name="cdc.gov"/> Most NPIs are simple, requiring little effort to put into practice, and, if implemented correctly, could save millions ofmany lives.{{cn|date=April 2023}}

Hand washing can be done with soap and water, or with alcohol-based hand sanitizers. Hand washing is a practice already in use in many countries in order to prevent the spread of communicable diseasediseases. Although alcohol-based rubs may be too expensive in some settings, soap and water hand sanitisationsanitization is amongone of the most cost-effective preventativepreventive measures.<ref name=":0" />

Respiratory etiquette refers to the methods a person uses to prevent transmission of disease when coughing or sneezing. This includes covering the mouth with the hand, elbow, or sleeve while in the process of coughing or sneezing, as well as proper disposal or washing of the contaminated material used to cover the mouth after a cough or sneeze has occurred. Like proper hand hygiene, this is a cost-effective intervention type.<ref name=":0" />

Face masks can be worn to reduce person-to-person transmission of respiratory disease. Typically, they do not protect the wearer, since they only protect against respiratory infection, but they reduce the risk of respiratory transmission from the wearer to others. Medical masks are used in health carehealthcare settings even during times when there is not a pandemic. During a pandemic, it is recommended that symptomatic individuals wear disposable medical grade masks at all times when exposed to others, and that asymptomatic members of the public wear face masks during severe pandemics to reduce transmission. Although the [[World Health Organization]] (WHO) recommended against the use of reusable cloth masks in 2019,<ref name=":0" /> it now suggests their use by the general public when physical distancing is not feasible, as part of its "Do it all!" approach to the COVID-19 pandemic.<ref>{{Cite web | date=2020-10-09|title=Coronavirus disease (COVID-19): Masks|url=https://www.who.int/news-room/q-a-detail/coronavirus-disease-covid-19-masks|url-status=live|archive-url=https://web.archive.org/web/20201126054145/https://www.who.int/news-room/q-a-detail/coronavirus-disease-covid-19-masks|archive-date=2020-11-26|access-date=2020-11-26|website=www.who.int|publisher=[[World Health Organization]]|language=en}}</ref>

[[Ultraviolet germicidal irradiation|Ultraviolet]] (UV) light can be used to destroy microorganismsmicro-organisms that exist in the environment. The installation of UV light fixtures can be costly and time consuming; it is unlikely that they could be used at the outbreak of an epidemic. There are possible health concerns involving UV light, as it may cause cancer and eye problems. The WHO does not recommend its use.<ref name=":0" />

Increased ventilation of a room through opening a window or through mechanized ventilation systems may reduce transmission within the room. Although opening a window may introduce allergens and air pollution, or, in some climates, cold air, it is overall a cheap and effective intervention type of intervention, and theits advantages likelyprobably outweigh theits disadvantages.<ref name=":0" />

Viruses such as [[influenza]] and [[coronavirus]] thrive in cold, dry environments, and increasing the humidity of a room may decreasereduce their transmission.<ref>{{cite journal | vauthors = Mecenas P, Bastos RT, Vallinoto AC, Normando D | title = Effects of temperature and humidity on the spread of COVID-19: A systematic review | journal = PLOS ONE | volume = 15 | issue = 9 | pages = e0238339 | date = 2020-09-18 | pmid = 32946453 | pmc = 7500589 | doi = 10.1371/journal.pone.0238339 | bibcode = 2020PLoSO..1538339M | doi-access = free }}</ref> Higher humidity, however, may cause [[mold]] and [[mildew]], which may in turn cause respiratory issuesproblems. The purchase of [[humidifierHumidifier]]s isare also expensive and supplieswill would likelyprobably be in short supply at the outsetstart of an epidemic.<ref name=":0" />

Contact tracing involves identifying individuals thatwith whom an infected person may have been in close contact with, and notifying those peoplethem that they may have been exposed to the infection. Contact tracing is a measure that brings with ithas ethical implications, in that it involves invading the privacy of the infected person. It also brings with it a large resource cost, as it requires trained personnel to perform the tracing. Less wealthy countries may not be able to mobilize a contact tracing task force. Contact tracing is likely to lead to an increase toin those in quarantine. Overall, it may be justified, in that it can reduce the spread of disease at the outsetstart of a pandemic, and allows for early identification of cases in those who werehave been exposed to an infected person.<ref name=":0" />

Infected individuals may be restricted in their movements or isolated away from others, either at home or atin a health carehealthcare facility, or atin another designated location. This isolation may either be voluntary (self-isolation), or mandatory. Although voluntary self-isolation is considered to be a low ethical risk, as it is common practice in many areas for someone who is sick to stay at home, mandatory isolation brings with it ethical concerns, such as freedom of movement and social stigma. There is a higher risk forthat infected individuals who share their homes with others towill transmit their disease, such as to a family member or roommate. An isolated individual may also be financially impactedaffected by their inability to continue to go to work. Overall, isolation of the sick is widely accepted as an intervention type among health professionals and policy makers, thoughalthough acceptance among the public varies.<ref name=":0" />

Quarantine involves the voluntary or imposed confinement of potentially non-ill persons who have been exposed to an illness, regardless of ifwhether they have contracted it. Quarantine will often happen at the home, but it may happen elsewhere, such as aboard ships (maritime quarantine) or airlines (onboard quarantine). Like isolation of sick individuals, forced quarantine of exposed individuals brings with it ethical concerns, thoughalthough in this case the concerns may be greater; quarantine involves restricting the movement of those who may otherwise be finewell, and in some cases may even cause them greater risk if they are quarantining with the sick person whoto whom they were exposed to, such as a sick family member or roommate whowith whom they live with. Like isolation, quarantine brings with it financial risk, duebecause toof work absenteeism.<ref name=":0" />

Measures taken involving schools range from making changes to operations within schools, to complete school closures. Lesser measures may involve reducing the density of students, such as by distancing desks, cancelling activities, reducing class sizes, or staggering class schedules. Sick students may be isolated from the greater student body, such as by having them stay at home or otherwise segregatedsegregate awaythem from other students.

More drastic measures include class dismissal, in which classes are cancelled but the school stays open to provide childcare to some children, and complete school closure. Both measures may either be either reactive or proactive: In a reactive case, the measure takes place after an outbreak has occurred withinin the school; in a proactive case, the measure takes place in order to prevent spread within the community.

Closures of schools may have an impact onaffect the families of affected children, especially low-income families. Parents may be forced to miss work to care for their children, affecting financial stability; children may also miss out on free school meals, causing nutritional concerns. Long absences from schools duebecaue toof closureclosures can also have negative effects on the students' education.<ref name=":0" />

Measures taken in the workplace include: [[remote work]]; [[paid leave]]; staggering shifts such that arrival, exit, and break times are different for each employee; reduced contact; and extended weekends.

AWorkplace closure is a more drastic measure is workplace closure. The financial effect of workplace closure on both the individual and the economy couldcan be severe. WhereWhen [[remote work]] is not possible, such as in the essential services, businesses may not be able to comply with guidelines. OneIn one simulation study found that school closure coupled with 50% absenteeism in the workplace would have had the highest financial impact of all the scenarios it looked atstudied, thoughalthough some studies have found that the combination would be effective atin decreasingreducing both the [[attack rate]] and the height of an epidemic.

One benefit of workplace closuresclosure is that when used in conjunction with school closures they would avoid the need for parents to make childcare arrangements for children who are staying homeaway from school.

The WHO recommends workplace closuresclosure only in the case of extraordinarily severe epidemics and pandemics.<ref name=":0" />

Avoiding crowding may involve: avoiding crowded areas such as shopping centres and transportation hubs; closing public spaces and banning large gatherings, such as sports events or religious activities; or setting a limit on small gatherings, such as limiting them to no more than fivea few people. There are negative consequences to the banning of gatherings; banning cultural or religious activities, for example, may prevent access to support in a time of crisis. Gatherings also allow for sharing of information, which can provide comfort and reduce fear.

{{Main|Travel advice}}Travel advice involves notifying potential travelers that they may be entering a zone that is affected by a disease outbreak. It allows for informed decisions to be made before travel, and it increases awareness when the traveler is withinin the destination country. Public awareness campaigns have been used in the past for areas impactedaffected by infectious diseases such as [[Dengue virus|dengue]], [[malaria]], [[Middle East respiratory syndrome–related coronavirus|Middle East respiratory syndrome]], and [[Influenza A virus subtype H1N1|H1N1]] influenza. Although such awareness campaigns may decreasereduce exposure among those traveling abroad, they may cause economic impact, dueowing to reduced travel in countries thatabout which the advice has been issued about. Overall, this intervention type is considered both feasible and acceptable.<ref name=":0" />

Entry and exit screening involves the screening of travelers at [[Port of entry|ports of entry]] for symptoms of illness. Measures include: health declarations, in which travelers make a decelerationdeclaration that they have not recently had symptoms of illness; visual inspections by the screening agent of the traveler; and the use of [[non-contact thermography]], in which a device such as a [[thermographic camera]] is used to measure the traveler's body temperature, in order to determine if they have a fever. Such a method may be circumvented by the traveler through the use of [[antipyretic]]s before travel in order to reduce fever. More intensive measures such as [[molecular diagnostics]] and [[Point-of-care testing|point-of-care]] [[Rapid antigen test|rapid antigen detection tests]] may also be used, but they carry with them a high resource cost, and may not be able to be appliedapplicable to a large number of travelers. A substantial number of resources may be needed in order to train staff and acquire equipment.

Although there is likelyprobably no harm to the traveler by the use of this intervention type of intervention, a limitation of it is that travelers may be asymptomatic uponon arrival, and symptoms may not show until several days after entry, at which point they may have already exposed others to their illness. There are also ethical concerns involving invading the privacy of the traveler. Screening is considered by the WHO to be both acceptable and feasible, though they did not recommend its use in the case of influenza outbreak due to its inefficacy in identifying asymptomatic individuals.<ref name=":0" />

Travel within a country may be restricted in order to delay the spread of disease. Restriction of travel within a country is likely to slow the spread of disease, thoughbut not prevent it entirely. Its use would be most effective at the outsetstart of a localized and extraordinarily severe pandemic for only a short period of time. It would only be effective if the measures were strict: while a 90% restriction was projected to delay spread by one or two weeks, a 75% restriction saw no effect. An analysis of the spread of influenza in [[United States|America]] following complete airline closures due to the [[September 11 attacks]] saw a reduction of itsreduced spread by thirteen13 days as compared towith previous years.

Restricting travel brings both ethical, and in many countries, legal challenges. [[Freedom of movement]] is considered in many places to be a human right, and its restriction may have an adverse impacteffect, particularly among vulnerable populations, such as migrant workers and those traveling to seek medical attention. Although 37% of the Member States of the WHO included internal travel restrictions as a part of their pandemic preparedness plan as of 2019, some of those countries may face legal challenges in implementing them, duebecause toof their own laws. Such restrictions may also bring economic impacteffects duebecause toof disruption in the supply chain.<ref name=":0" />

Border closure is a measure that involves complete or severe restriction of travel across [[border]]s. TheThis measurehad sawa positivebeneficial effect in delaying the delayspread of cases of influenza during the 1918 Influenzainfluenza Pandemicpandemic, and was predicted to delay epidemic spread between [[Hong Kong]] and [[mainland China]] by 3.5 weeks. While border closure is expected to slow the spread of infection, it is not expected to reduce epidemicthe duration of an epidemic. Strict border closure in island nations could be effective, thoughalthough supply chain issuesprobelms may cause adverse disruptions.

Supply chain issuesproblems due to border closure are likely to cause disruption of essential goods, such as food and medicationmedications, as well as serious economic impacteffects. They may have adverse impacteffects on the daily lives of individuals. As well, borderBorder closure brings withalso ithas serious ethical implications, because, like internal travel restrictions, it involves restricting the movements of individuals. It should only be used as a voluntary measure to the maximum extent possible. There may also be stigmatization of individuals from affected areas.

Border closure would be most feasible at the very outsetstart of a pandemic. The WHO recommended it only in extraordinary circumstances, and requestedasked that they be notified by any nation implementing it.<ref name=":0" />

Non-pharmaceuticalpharmacological interventions were widely adopted during the 1918 flu outbreak – most famously, the radical quarantine of [[Gunnison, Colorado]] resulted in sparing the town the worst of the earlier waves of the pandemic.<ref name="auto"/> Interventions used included the wearing of face masks, isolation, quarantine, personal hygiene, use of disinfectants, and limits on public gatherings. At the time, the science behind NPIs was new, and was not applied consistently in every area. Retroactive studies on the outbreak have foundshown that the measures were effective in mitigating the spread of the fluinfection.<ref>{{Cite web|title=The 1918 Flu Pandemic: Why It Matters 100 Years Later {{!}} Blogs {{!}} CDC|url=https://blogs.cdc.gov/publichealthmatters/2018/05/1918-flu/|url-status=live|archive-url=https://web.archive.org/web/20211223010523/https://blogs.cdc.gov/publichealthmatters/2018/05/1918-flu/|archive-date=2021-12-23|access-date=2021-12-22|website=Centers for Disease Control and Infection|date=14 May 2018 |language=en-us}}</ref><ref>{{Cite journal|last1=Markel|first1=Howard|last2=Lipman|first2=Harvey B.|last3=Navarro|first3=J. Alexander|last4=Sloan|first4=Alexandra|last5=Michalsen|first5=Joseph R.|last6=Stern|first6=Alexandra Minna|last7=Cetron|first7=Martin S.|date=2007-08-08|title=Nonpharmaceutical Interventions Implemented by US Cities During the 1918-1919 Influenza Pandemic|journal=JAMA|volume=298|issue=6|pages=644–654|doi=10.1001/jama.298.6.644|pmid=17684187 |issn=0098-7484|doi-access=free}}</ref>

The use of non-pharmaceuticalpharmacological interventions during the 1918 flu pandemic also gave rise to new societal concerns. There was a growing awareness of "overreacting" and "under-reacting" amongstamong U.S. public health authorities, and these opposing perspectives often added to the uncertainties inherent in thisthe epidemic. Likewise, public perceptions varied with respect to adherence to public health guidelines, giving rise to terms such as "mask slackers" and "careless consumptives."<ref>{{Cite journal |last=Tomes |first=Nancy |date=2010 |title="Destroyer and Teacher": Managing the Masses During the 1918–1919 Influenza Pandemic |journal=Public Health Reports |volume=125 |issue=Suppl 3 |pages=48–62 |doi=10.1177/00333549101250S308 |issn=0033-3549 |pmc=2862334 |pmid=20568568}}</ref>

{{See also|Face masks during the COVID-19 pandemic|COVID-19 lockdowns}}[[COVID-19]] is a disease caused by the [[SARS-CoV-2]] virus, thatwhich spread from China, to becomecreating a [[COVID-19 pandemic|pandemic]].<ref>Li LQ, Huang T, Wang YQ, Wang ZP, Liang Y, Huang TB, Zhang HY, Sun W, Wang Y. COVID-19 patients' clinical characteristics, discharge rate, and fatality rate of meta-analysis. J Med Virol. 92(6):577-583. 2020.</ref> Several [[COVID-19 vaccine]]s are now being used, with 6.54 billion doses having been administered worldwide as of 12 October 2021.<ref>{{cite journal |title=Coronavirus (COVID-19) Vaccinations – Statistics and Research|url=https://ourworldindata.org/covid-vaccinations|access-date=12 October 2021|journal=Our World in Data|date=5 March 2020|last1=Ritchie|first1=Hannah|last2=Mathieu|first2=Edouard|last3=Rodés-Guirao|first3=Lucas|last4=Appel|first4=Cameron|last5=Giattino|first5=Charlie|last6=Ortiz-Ospina|first6=Esteban|last7=Hasell|first7=Joe|last8=MacDonald|first8=Bobbie|last9=Beltekian|first9=Diana|last10=Roser|first10=Max}}</ref>

In the early stages of the COVID-19 pandemic, before vaccines had been developed, NPIs were key toin mitigation ofmitigating infections and reduction ofreducing COVID-19-related mortality. Some NPIs have remained in place after extensive vaccination.<ref>{{cite news |last1=Anon |title=Coronavirus: Israel reimposes masks amid new virus fears |work=BBC News |date=25 June 2021 |url=https://www.bbc.co.uk/news/world-middle-east-57594155 |access-date=12 October 2021}}</ref> One report identified over 500 specific NPIs for controlling transmission and spread of the [[SARS-CoV-2]] virus; most of these have been tried in practice.<ref name=autogenerated2 /> Evidence suggests that highly effective strategies include closing schools and universities,<ref name=autogenerated1>{{Cite journal|url=https://doi.org/10.1126/science.abd9338|doi=10.1126/science.abd9338 |issn=0036-8075|title=Inferring the effectiveness of government interventions against COVID-19|year=2021|last1=Brauner|first1=Jan M.|last2=Mindermann|first2=Sören|last3=Sharma|first3=Mrinank|last4=Johnston|first4=David|last5=Salvatier|first5=John|last6=Gavenčiak|first6=Tomáš|last7=Stephenson|first7=Anna B.|last8=Leech|first8=Gavin|last9=Altman|first9=George|last10=Mikulik|first10=Vladimir|last11=Norman|first11=Alexander John|last12=Monrad|first12=Joshua Teperowski|last13=Besiroglu|first13=Tamay|last14=Ge|first14=Hong|last15=Hartwick|first15=Meghan A.|last16=Teh|first16=Yee Whye|last17=Chindelevitch|first17=Leonid|last18=Gal|first18=Yarin|last19=Kulveit|first19=Jan|journal=Science|volume=371|issue=6531|pmid=33323424|pmc=7877495|hdl=10044/1/86864 }}</ref> banning large gatherings,<ref name=autogenerated1 /> and wearing face masks.<ref>{{Cite journal|url=https://doi.org/10.1001/jama.2021.1505|doi = 10.1001/jama.2021.1505 |issn=0098-7484|title = Effectiveness of Mask Wearing to Control Community Spread of SARS-CoV-2|year = 2021|last1 = Brooks|first1 = John T.|last2 = Butler|first2 = Jay C.|journal = JAMA|volume = 325|issue = 10|pages = 998–999|pmid = 33566056|pmc = 8892938 |s2cid = 231868838}}</ref>