Monkeypox 2022:  Is there a case for quarantine?

Authored by: Prof. Dr. Kristi L. Koenig, MD, FACEP, FIFEM, FAEMS, Prof. Dr. Aileen M. Marty, MD, FCAP, and Christian K. Beÿ, MPH, NREMT (see below for author bios)

Last updated: 15 July 2022

Quarantine versus Isolation

After more than two years of dealing with the health emergency caused by the COVID-19 pandemic, many people remain confused about the difference between “quarantine” and “isolation.” The distinction is important. While most would agree that persons confirmed to have a contagious infection should be separated from non-infected people (isolation), the concept of quarantining potentially infected persons is more controversial. Both strategies require physical separation and confinement of individuals to prevent disease transmission and protect public health; however, they are not synonymous.[1] Quarantine applies to healthy (asymptomatic) individuals after exposure to a contagious disease when there is a possibility of transmitting the disease without symptoms. Isolation is used for contagious (usually symptomatic) people.

Monkeypox 2022

Monkeypox 2022, a re-emerging disease, once more highlights the need to apply the best available evidence to create clear, concise guidance for the potential use of quarantine as a public health tool.[2],[3],[4],[5] Humanitarians and policymakers should consider when and how to implement quarantine – with the goal of saving lives and protecting livelihoods – based on scientific evidence, while avoiding undue restrictions on civil liberties and negative economic consequences.

Monkeypox can cause disease in many animals, and animal-to-human transmission is well documented.[6] Reverse zoonosis, i.e., the transmission of monkeypox from humans to animals, is also a serious concern, particularly for animals with known susceptibility to monkeypox. High-risk animals include pet rodents (e.g., hamsters, guinea pigs, Prairie dogs),[7] lagomorphs (e.g., rabbits, hares, pikas)[8], and non-human primates. Equally problematic is reverse zoonosis to susceptible urban wildlife, such as squirrels.[9] While reverse zoonosis is not yet documented,[10] it is a serious public health concern, as highlighted in the June 2022 discussions at the World Health Organization (WHO) International Health Regulation Emergency Committee meeting.[11]

Following the first detection of human monkeypox on 7 May 2022[12],[13] in the UK, a country outside of the endemic regions of Central and West Africa, the outbreak spread rapidly around the globe and showed growing evidence of sustained human-to-human and community transmission.11 On 29 May 2022, the WHO noted that “this is the first time that monkeypox cases and clusters are reported concurrently in widely disparate WHO geographical areas, and without known epidemiological links to endemic countries.”[14] By 15 July 2022, confirmed human monkeypox cases rose to 12,333 in at least 62 non-endemic nations, encompassing every continent other than Antarctica.[15] Data suggest that the monkeypox virus has likely been circulating for some time[16] and has now manifested dramatically in social networks that facilitate increased human-to-human transmission.

Application of Quarantine to Monkeypox

Would quarantining asymptomatic close contacts be of public health benefit during this unprecedented global monkeypox 2022 outbreak? Preliminary public guidance has been contradictory. For example, on 23 May 2022, only a short time after the initial cases were reported, US President Biden stated that quarantine was unnecessary.[17] Conversely, three days earlier, Belgium reportedly had already become the first country to implement a mandatory 21-day quarantine for persons infected with monkeypox,[18] an incorrect application of the word quarantine. Similarly, on 23 June 2022, the UK seemingly confused the terms quarantine and isolation by publishing guidelines that included directions on “self-isolation” for exposed persons. Specifically, the guidance stated, “health officials have said that those with high exposure risks should self-isolate for 21 days, including household contacts or medical professionals who have worked with infected patients.”[19] This guidance represents an incorrect application of the word isolation. These mixed messages and inconsistent policies contribute to a lack of understanding of the terms isolation and quarantine.

Implementing a quarantine on exposed healthcare workers, especially for the full 21-day incubation period of monkeypox, could have profound negative consequences. Such a quarantine could exacerbate the already existing severe staffing shortages in prehospital, hospital, nursing home, and other healthcare settings. Quarantine-induced shortages of personnel working in other essential, critical infrastructure positions, e.g., manufacturing of healthcare supplies and equipment, could lead to supply chain disruptions. Quarantine invariably affects all of society and results in profound, sustained deleterious psychological, social, and economic consequences.

Evidence-Based Considerations

When applied correctly, quarantine and isolation are valuable public health tools that can improve the health outcomes of populations by inhibiting disease spread. Before implementing quarantine, isolation, or both, decision-makers need to consider whether the resulting reduction in disease spread from using these tools produces a greater net benefit for society compared with not implementing these tools. Additionally, decision-makers must consider alternate methods to reduce disease spread if isolation and quarantine are anticipated to have negative psychosocial and economic consequences.

Generally, isolation and quarantine do not directly benefit individuals. While the science is evolving, as of early July 2022, data indicate that monkeypox can be transmitted from persons who are unaware they are infected and who may be asymptomatic. Alternatively, they may have non-specific prodromal symptoms not attributable to monkeypox. As these persons do not appear infected, if they have been exposed to monkeypox, a quarantine of up to 21 days, the outer range of the incubation period, could be considered. However, aggressive symptom monitoring, non-pharmacological interventions (e.g., masking, social distancing), and strict adherence to hygienic practices might be more sensible and practical alternatives that preserve the workforce. Additionally, if a worker has had contact with vulnerable populations, e.g., pregnant and other immunocompromised patients or people at extremes of age, it would be desirable to avoid future contact with those populations, even if not implementing a full quarantine, until the exposed person is confirmed not to have monkeypox.


Community transmission of monkeypox 2022 in numerous previously non-endemic regions of the world is ongoing. Detected cases almost certainly underestimate the actual disease prevalence. The strong possibility that persons may be infectious before recognizing that they have monkeypox means that quarantine should be considered, at least for people who would otherwise have contact with vulnerable populations.

Quarantine is one of several key public health policy considerations that the monkeypox 2022 outbreak underscores. To assist frontline clinicians and humanitarian aid workers in the rapid and appropriate management of patients with suspected monkeypox, building on prior work,[20],[21],[22],[23],[24],[25],[26],[27],[28] we have developed a novel Identify-Isolate-Inform (3I) Tool, accompanied by a manuscript that provides a comprehensive review of the existing evidence.[29]

Avoiding inconsistent infection-control terminology reduces confusion, especially during the ongoing COVID-19 pandemic. Scientists must inform policymakers about the evolving knowledge base, and policymakers must provide clear and accurate information to the public that is updated as the science progresses. Evidence-based mitigation measures, standardized worldwide, are urgently needed to maximize the ability to contain the spread of the monkeypox virus before it progresses into an even more serious pandemic and produces new endemic regions across the globe.

Author Biographies

Prof. Dr. Kristi L. Koenig is Professor Emerita of Emergency Medicine and Public Health, University of California, Irvine, USA. Professor Koenig, an internationally recognized expert in Disaster Medicine, Emerging Infectious Diseases, Surge Capacity, and Crisis Care, is the founding director of the UC Irvine Center for Disaster Medical Sciences. A Fulbright Scholar and Fellow of the International Federation for Emergency Medicine, she has published a definitive Disaster Medicine text, authored more than 140 peer-reviewed articles, and delivered more than 540 invited lectures in about 35 countries. Dr. Koenig previously held a 5-year appointment with the federal government as National Emergency Management Director for the Department of Veterans Affairs. During the 2014 Ebola outbreak, Dr. Koenig served on the national ACEP Ebola Expert Task Force and as Co-Editor of the Disaster Medicine and Public Health Preparedness Journal Special Ebola Issue. In this capacity, she developed the Identify-Isolate-Inform algorithm adopted by the U.S. Centers for Disease Control and Prevention for the emergency department, EMS, and ambulatory care center preparedness for Ebola. A board-certified Emergency and EMS Physician, she served as the Director of Public Health Preparedness for the University of California at Irvine from October 2004 to January 2017 before accepting a position as County of San Diego EMS Medical Director, where she is responsible for prehospital care for a population of 3.4 million, spread over more than 4,500 square miles.

Prof. Dr. Aileen M. Marty is a Distinguished University Professor of Infectious Diseases and Outbreak response at Florida International University (FIU); Laboratory Director and Clinical Consultant for the FIU-Health Auxiliary, High Complexity CLIA laboratory; Director of the FIU Health Travel Medicine Program and Vaccine Clinic; and Commander for Emergency Response Team Development. She is also the Outbreak Response Commander for the FIU-Florida Advanced Surgical Transport team (FIU-FAST), Senior Advisor for the World Health Organization on the Health Security Interphase and Mass Gatherings, and co-Editor-In-Chief for the One Health Journal by Elsevier. Dr. Marty is a physician-scientist with decades of clinical and research experience. She has more than 45 years of research experience. Her research began in 1976 with work on vision studies in the lemon shark (Negaprion brevirostris) and spans sizeable clinical research studies involving helminthic infections and drug interactions (e.g., onchocerciasis and ivermectin studies), clinic-pathological studies on the health impact of vaccines (Venezuela encephalitis virus) on humans and rodents, epidemiological and laboratory studies on disease (leprosy in non-human primates), and the pathogenesis of Ebola virus on non-human primates, multiple studies on SARS-CoV-2, Zika, disease surveillance, immunology, and the public health impact of disease, including legal, medical, and sociological factors. Dr. Marty has served on multiple national, regional, and international boards. This work includes serving for the World Health Organization with Mass Gathering Medicine and the Health Security Interface, working for the United Nations as a Weapons Inspector, and working at the White House for the National Security Council and as a Presidential Advisor.

Christian K. Beÿ is an analyst for the Emergency Medical Services (EMS) Office of the County of San Diego, California. His research interests include EMS, search and rescue, disaster medicine, and public health. In addition to his research activities, he has supported COVID-19 response efforts as a practicing prehospital professional.



[1] Hodge JG, Gostin LO. Chapter 17: Quarantine. In: Koenig KL, Schultz CH, eds. Koenig and Schultz’s Disaster Medicine: Comprehensive Principles and Practices. 2nd ed. Cambridge University Press, New York; 2016:241–249.

[2] Koenig KL. The Quarantine Conundrum: Perspectives for the humanitarian community. Evidence Aid. March 14, 2017. Accessed June 27, 2022.

[3] Koenig KL. COVID-19: A Call for Science-Informed Management. Evidence Aid. March 3, 2020. Accessed June 27, 2022.

[4] Barbisch D, Koenig KL, Shih FY. Is There a Case for Quarantine? Perspectives from SARS to Ebola. Disaster Med Public Health Prep. 2015;9(5):547-553. DOI:10.1017/dmp.2015.38

[5] Koenig KL. Health care worker quarantine for Ebola: to eradicate the virus or alleviate fear? Ann Emerg Med. 2015;65(3):330-331. DOI:10.1016/j.annemergmed.2014.12.003

[6] Monkeypox: Past U.S. Cases and Outbreaks. Centers for Disease Control and Prevention. Reviewed June 6, 2022. Accessed June 27, 2022.

[7] Monkeypox: African Rodent Importation Ban Embargoed African Rodents and Monkeypox Virus. Centers for Disease Control and Prevention. Reviewed May 11, 2015. Accessed June 27, 2022.

[8] Maskalyk J. Monkeypox outbreak among pet owners. CMAJ. 2003;169(1):44-45.

[9] Di Giulio DB, Eckburg PB. Human monkeypox: an emerging zoonosis. Lancet Infect Dis. 2004;4(1):15-25. DOI: 10.1016/s1473-3099(03)00856-9

[10] World Health Organization. Multi-country monkeypox outbreak: situation update. 27 June 2022

[11] Meeting of the International Health Regulations (2005) Emergency Committee regarding the multi-country monkeypox outbreak. World Health Organization. June 25, 2022. Accessed June 27, 2022.–regarding-the-multi-country-monkeypox-outbreak

[12] Monkeypox cases confirmed in England – latest updates. UK Health Security Agency. Updated June 21, 2022. Accessed June 26, 2022.

[13] Minhaj FS, Ogale YP, Whitehill F, et al. Monkeypox Outbreak — Nine States, May 2022. MWR Morb Mortal Wkly Rep. 2022;71(23):764–769. DOI: 10.15585/mmwr.mm7123e1

[14] Multi-country monkeypox outbreak in non-endemic countries: Update. World Health Organization. May 29, 2022. Accessed June 27, 2022.

[15] 2022 Monkeypox Outbreak Global Map. Centers for Disease Control and Prevention. Updated July 1, 2022. Accessed July 1, 2022.

[16] Perez Duque M, Ribeiro S, Martins JV, et al. Ongoing monkeypox virus outbreak, Portugal, 29 April to 23 May 2022. Euro Surveill. 2022;27(22):2200424. DOI: 10.2807/1560-7917.ES.2022.27.22.2200424

[17] Kim SM. Biden says quarantines for monkeypox aren’t needed in U.S. Washington Post. May 23, 2022. Accessed June 27, 2022.

[18] Gilchrist K. Belgium becomes first country to introduce mandatory monkeypox quarantine as global cases rise. CNBC. Updated May 23, 2022. Accessed June 27, 2022.

[19] Monkeypox contact tracing guidance: classification of contacts and advice for vaccination and follow up. UK Health Security Agency. Updated June 23, 2022. Accessed June 27, 2022.

[20] Koenig KL. Identify, isolate, inform: a 3-pronged approach to management of public health emergencies. Disaster Med Public Health Prep. 2015;9(1):86-87. doi:10.1017/dmp.2014.125

[21] Koenig KL, Alassaf W, Burns MJ. Identify-Isolate-Inform: A Tool for Initial Detection and Management of Measles patients in the Emergency Department. West J Emerg Med. 2015;16(2):212-219. DOI: 10.5811/westjem.2015.3.25678

[22] Koenig KL. Identify-Isolate-Inform: A Modified Tool for Initial Detection and Management of Middle East Respiratory Syndrome Patients in the Emergency Department. West J Emerg Med. 2015;16(5):619-624. DOI: 10.5811/westjem.2015.7.27915

[23] Koenig KL, Shastry S, Mzahim B, et al. Mumps Virus: Modification of the Identify-Isolate-Inform Tool for Frontline Healthcare Providers. West J Emerg Med. 2016;17(5):490-496. DOI: 10.5811/westjem.2016.6.30793

[24] Koenig KL, Almadhyan A, Burns MJ. Identify-Isolate-Inform: A Tool for Initial Detection and Management of Zika Virus Patients in the Emergency Department. West J Emerg Med. 2016;17(3):238-244. DOI: 10.5811/westjem.2016.3.30188

[25] Koenig KL, Shastry S, Burns MJ. Hepatitis A Virus: Essential Knowledge and a Novel Identify-Isolate-Inform Tool for Frontline. Healthcare Providers. West J Emerg Med. 2017;18(6):1000-1007. DOI: 10.5811/westjem.2017.10.35983

[26] Koenig KL, Farah J, Thihalolipavan S, et al. Pertussis: The Identify, Isolate, Inform Tool Applied to a Re-emerging Respiratory Illness. West J Emerg Med. 2019;20(2):191-197. DOI: 10.5811/westjem.2018.11.40023

[27] Cheng T, Mzahim B, Koenig KL, et al. Scabies: Application of the Novel Identify-Isolate-Inform Tool for Detection and Management. West J Emerg Med. 2020;21(2):191-198. DOI: 10.5811/westjem.2020.1.46120

[28] Koenig KL, Beÿ CK, McDonald EC. 2019-nCoV: The Identify-Isolate-Inform (3I) Tool Applied to a Novel Emerging Coronavirus. West J Emerg Med. 2020;21(2):184-190. Published 2020 Jan 31. doi:10.5811/westjem.2020.1.46760

[29] Koenig KL, Beÿ CK, Marty AM. Monkeypox 2022 Identify-Isolate-Inform: A 3I Tool for Frontline Clinicians for a Zoonosis with Escalating Human Community Transmission. In Press. DOI: 10.1016/j.onehlt.2022.100410