Individual quarantine versus active monitoring of contacts for the mitigation of COVID-19: a modelling study
Corey M Peak, Rebecca Kahn, Yonatan H Grad, Lauren M Childs, Ruoran Li, Marc Lipsitch, Caroline O Buckee, Corey M Peak, Rebecca Kahn, Yonatan H Grad, Lauren M Childs, Ruoran Li, Marc Lipsitch, Caroline O Buckee
Abstract
Background: Voluntary individual quarantine and voluntary active monitoring of contacts are core disease control strategies for emerging infectious diseases such as COVID-19. Given the impact of quarantine on resources and individual liberty, it is vital to assess under what conditions individual quarantine can more effectively control COVID-19 than active monitoring. As an epidemic grows, it is also important to consider when these interventions are no longer feasible and broader mitigation measures must be implemented.
Methods: To estimate the comparative efficacy of individual quarantine and active monitoring of contacts to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we fit a stochastic branching model to reported parameters for the dynamics of the disease. Specifically, we fit a model to the incubation period distribution (mean 5·2 days) and to two estimates of the serial interval distribution: a shorter one with a mean serial interval of 4·8 days and a longer one with a mean of 7·5 days. To assess variable resource settings, we considered two feasibility settings: a high-feasibility setting with 90% of contacts traced, a half-day average delay in tracing and symptom recognition, and 90% effective isolation; and a low-feasibility setting with 50% of contacts traced, a 2-day average delay, and 50% effective isolation.
Findings: Model fitting by sequential Monte Carlo resulted in a mean time of infectiousness onset before symptom onset of 0·77 days (95% CI -1·98 to 0·29) for the shorter serial interval, and for the longer serial interval it resulted in a mean time of infectiousness onset after symptom onset of 0·51 days (95% CI -0·77 to 1·50). Individual quarantine in high-feasibility settings, where at least 75% of infected contacts are individually quarantined, contains an outbreak of SARS-CoV-2 with a short serial interval (4·8 days) 84% of the time. However, in settings where the outbreak continues to grow (eg, low-feasibility settings), so too will the burden of the number of contacts traced for active monitoring or quarantine, particularly uninfected contacts (who never develop symptoms). When resources are prioritised for scalable interventions such as physical distancing, we show active monitoring or individual quarantine of high-risk contacts can contribute synergistically to mitigation efforts. Even under the shorter serial interval, if physical distancing reduces the reproductive number to 1·25, active monitoring of 50% of contacts can result in overall outbreak control (ie, effective reproductive number <1).
Interpretation: Our model highlights the urgent need for more data on the serial interval and the extent of presymptomatic transmission to make data-driven policy decisions regarding the cost-benefit comparisons of individual quarantine versus active monitoring of contacts. To the extent that these interventions can be implemented, they can help mitigate the spread of SARS-CoV-2.
Funding: National Institute of General Medical Sciences, National Institutes of Health.
Copyright © 2020 Elsevier Ltd. All rights reserved.
Figures
References
- Centers for Disease Control and Prevention Social distancing. May 6, 2020.
- Qin A, Myers SL, Yu E. China tightens Wuhan lockdown in ‘wartime’ battle with coronavirus. The New York Times. Feb 6, 2020
- McCarthy IO, Wojno AE, Joseph HA, Teesdale S. Check and Report Ebola (CARE) Hotline: the user perspective of an innovative tool for postarrival monitoring of Ebola in the United States. JMIR Public Health Surveill. 2017;3:e89.
- Fraser C, Riley S, Anderson RM, Ferguson NM. Factors that make an infectious disease outbreak controllable. Proc Natl Acad Sci USA. 2004;101:6146–6151.
- Peak CM, Childs LM, Grad YH, Buckee CO. Comparing nonpharmaceutical interventions for containing emerging epidemics. Proc Natl Acad Sci USA. 2017;114:4023–4028.
- Hellewell J, Abbott S, Gimma A. Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts. Lancet Glob Health. 2020;8:e488–e496.
- Ferretti L, Wymant C, Kendall M. Quantifying SARS-CoV-2 transmission suggests epidemic control with digital contact tracing. Science. 2020 doi: 10.1126/science.abb6936. published online March 31.
- Wang D, Hu B, Hu C. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA. 2020 doi: 10.1001/jama.2020.1585. published online Feb 7.
- Rothe C, Schunk M, Sothmann P. Transmission of 2019-nCoV infection from an asymptomatic contact in Germany. N Engl J Med. 2020;382:970–971.
- Kupferschmidt K. Study claiming new coronavirus can be transmitted by people without symptoms was flawed. Science. Feb 3, 2020
- Nishiura H, Linton NM, Akhmetzhanov AR. Serial interval of novel coronavirus (2019-nCoV) infections. medRxiv. 2020 doi: 10.1101/2020.02.03.20019497. published online Feb 17. (preprint).
- Li Q, Guan X, Wu P. Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia. N Engl J Med. 2020;382:1199–1207.
- Riou J, Althaus CL. Pattern of early human-to-human transmission of Wuhan 2019 novel coronavirus (2019-nCoV), December 2019 to January 2020. Euro Surveill. 2020;25
- European Centre for Disease Prevention and Control Contact tracing: public health management of persons, including healthcare workers, having had contact with COVID-19 cases in the European Union. Feb 25, 2020.
- Chinese Center for Disease Control and Prevention COVID-19 prevention and control guidelines.
- Hsieh Y-H, King C-C, Chen CWS. Quarantine for SARS, Taiwan. Emerg Infect Dis. 2005;11:278–282.
- US Centers for Disease Control and Prevention CDC issues federal quarantine order to repatriated U.S. citizens at March Air Reserve Base. Jan 31, 2020.
- Ng Y, Li Z, Chua YX. Evaluation of the effectiveness of surveillance and containment measures for the first 100 patients with COVID-19 in Singapore — January 2–February 29, 2020. MMWR Morb Mortal Wkly Rep. 2020;69:307–311.
- Gostin LO, Bayer R, Fairchild AL. Ethical and legal challenges posed by severe acute respiratory syndrome: implications for the control of severe infectious disease threats. JAMA. 2003;290:3229–3237.
- Adalja AA, Toner E, Inglesby TV. Priorities for the US health community responding to COVID-19. JAMA. 2020 doi: 10.1001/jama.2020.3413. published online March 3.
- World Health Organization Report of the WHO-China joint mission on coronavirus disease 2019 (COVID-19)
- Backer JA, Klinkenberg D, Wallinga J. Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China, 20–28 January 2020. Euro Surveill. 2020;25
- Guan W-J, Ni Z-Y, Hu Y. Clinical characteristics of coronavirus disease 2019 in China. N Engl J Med. 2020 doi: 10.1056/NEJMoa2002032. published online Feb 28.
- Tindale L, Coombe M, Stockdale JE. Transmission interval estimates suggest pre-symptomatic spread of COVID-19. medRxiv. 2020 doi: 10.1101/2020.03.03.20029983. published online March 6. (preprint).
- Peak CM, Wesolowski A, Zu Erbach-Schoenberg E. Population mobility reductions associated with travel restrictions during the Ebola epidemic in Sierra Leone: use of mobile phone data. Int J Epidemiol. 2018;47:1562–1570.
Source: PubMed