1
|
Banuet-Martinez M, Yang Y, Jafari B, Kaur A, Butt ZA, Chen HH, Yanushkevich S, Moyles IR, Heffernan JM, Korosec CS. Monkeypox: a review of epidemiological modelling studies and how modelling has led to mechanistic insight. Epidemiol Infect 2023; 151:e121. [PMID: 37218612 PMCID: PMC10468816 DOI: 10.1017/s0950268823000791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 05/24/2023] Open
Abstract
Human monkeypox (mpox) virus is a viral zoonosis that belongs to the Orthopoxvirus genus of the Poxviridae family, which presents with similar symptoms as those seen in human smallpox patients. Mpox is an increasing concern globally, with over 80,000 cases in non-endemic countries as of December 2022. In this review, we provide a brief history and ecology of mpox, its basic virology, and the key differences in mpox viral fitness traits before and after 2022. We summarize and critique current knowledge from epidemiological mathematical models, within-host models, and between-host transmission models using the One Health approach, where we distinguish between models that focus on immunity from vaccination, geography, climatic variables, as well as animal models. We report various epidemiological parameters, such as the reproduction number, R0, in a condensed format to facilitate comparison between studies. We focus on how mathematical modelling studies have led to novel mechanistic insight into mpox transmission and pathogenesis. As mpox is predicted to lead to further infection peaks in many historically non-endemic countries, mathematical modelling studies of mpox can provide rapid actionable insights into viral dynamics to guide public health measures and mitigation strategies.
Collapse
Affiliation(s)
- Marina Banuet-Martinez
- Climate Change and Global Health Research Group, School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Yang Yang
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Behnaz Jafari
- Mathematics and Statistics Department, Faculty of Science, University of Calgary, Calgary, AB, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - Avneet Kaur
- Irving K. Barber School of Arts and Sciences, Department of Computer Science, Mathematics, Physics and Statistics, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Zahid A. Butt
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Helen H. Chen
- School of Public Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Svetlana Yanushkevich
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - Iain R. Moyles
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Jane M. Heffernan
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada
| | - Chapin S. Korosec
- Modelling Infection and Immunity Lab, Mathematics and Statistics, York University, Toronto, ON, Canada
- Centre for Disease Modelling, Mathematics and Statistics, York University, Toronto, ON, Canada
| |
Collapse
|
2
|
|
3
|
Breman JG, de Quadros CA, Dowdle WR, Foege WH, Henderson DA, John TJ, Levine MM. The role of research in viral disease eradication and elimination programs: lessons for malaria eradication. PLoS Med 2011; 8:e1000405. [PMID: 21311582 PMCID: PMC3026693 DOI: 10.1371/journal.pmed.1000405] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
By examining the role research has played in eradication or regional elimination initiatives for three viral diseases--smallpox, poliomyelitis, and measles--we derive nine cross-cutting lessons applicable to malaria eradication. In these initiatives, some types of research commenced as the programs began and proceeded in parallel. Basic laboratory, clinical, and field research all contributed notably to progress made in the viral programs. For each program, vaccine was the lynchpin intervention, but as the programs progressed, research was required to improve vaccine formulations, delivery methods, and immunization schedules. Surveillance was fundamental to all three programs, whilst polio eradication also required improved diagnostic methods to identify asymptomatic infections. Molecular characterization of pathogen isolates strengthened surveillance and allowed insights into the geographic source of infections and their spread. Anthropologic, sociologic, and behavioural research were needed to address cultural and religious beliefs to expand community acceptance. The last phases of elimination and eradication became increasingly difficult, as a nil incidence was approached. Any eradication initiative for malaria must incorporate flexible research agendas that can adapt to changing epidemiologic contingencies and allow planning for posteradication scenarios.
Collapse
Affiliation(s)
- Joel G. Breman
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - Walter R. Dowdle
- Task Force for Global Health, Decatur, Georgia, United States of America
| | - William H. Foege
- The Bill & Melinda Gates Foundation, Seattle, Washington, United States of America
| | - Donald A. Henderson
- Center for Biosecurity, University of Pittsburgh Medical Center, Baltimore, Maryland, United States of America
| | | | - Myron M. Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| |
Collapse
|
4
|
|
5
|
Longini IM, Halloran ME, Nizam A, Yang Y, Xu S, Burke DS, Cummings DAT, Epstein JM. Containing a large bioterrorist smallpox attack: a computer simulation approach. Int J Infect Dis 2007; 11:98-108. [PMID: 16899385 DOI: 10.1016/j.ijid.2006.03.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 03/07/2006] [Accepted: 03/15/2006] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND A bioterrorist release of smallpox is a constant threat to the population of the USA and other countries. DESIGN A stochastic simulation model of the spread of smallpox due to a large bioterrorist attack in a structured population was constructed. Disease natural history parameter estimates, time lines of behavioral activities, and control scenarios were based on the literature and on the consensus opinion of a panel of smallpox experts. RESULTS The authors found that surveillance and containment, i.e., isolation of known cases and vaccination of their close contacts, would be sufficient to effectively contain a large intentional smallpox release. Given that surveillance and containment measures are in place, preemptive vaccination of hospital workers would further reduce the number of smallpox cases and deaths but would require large numbers of prevaccinations. High levels of reactive mass vaccination after the outbreak begins would further reduce smallpox cases and deaths to a minimum, but would require even larger numbers of vaccinations. Reactive closure of schools would have a minimal effect. CONCLUSION A rapid and well-organized response to a bioterrorist attack would be necessary for effective surveillance and containment to control spread. Preemptive vaccination of hospital workers and reactive vaccination of the target population would further limit spread, but at a cost of many more vaccinated. This cost in resources and potential harm due to vaccination will have to be weighed against the potential benefits should an attack occur. Prevaccination of the general population is not necessary.
Collapse
Affiliation(s)
- Ira M Longini
- Program in Biostatistics and Biomathematics, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., LE-400, PO Box 19024, Seattle, WA 98109-1024, USA.
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Porco TC, Holbrook KA, Fernyak SE, Portnoy DL, Reiter R, Aragón TJ. Logistics of community smallpox control through contact tracing and ring vaccination: a stochastic network model. BMC Public Health 2004; 4:34. [PMID: 15298713 PMCID: PMC520756 DOI: 10.1186/1471-2458-4-34] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2004] [Accepted: 08/06/2004] [Indexed: 11/30/2022] Open
Abstract
Background Previous smallpox ring vaccination models based on contact tracing over a network suggest that ring vaccination would be effective, but have not explicitly included response logistics and limited numbers of vaccinators. Methods We developed a continuous-time stochastic simulation of smallpox transmission, including network structure, post-exposure vaccination, vaccination of contacts of contacts, limited response capacity, heterogeneity in symptoms and infectiousness, vaccination prior to the discontinuation of routine vaccination, more rapid diagnosis due to public awareness, surveillance of asymptomatic contacts, and isolation of cases. Results We found that even in cases of very rapidly spreading smallpox, ring vaccination (when coupled with surveillance) is sufficient in most cases to eliminate smallpox quickly, assuming that 95% of household contacts are traced, 80% of workplace or social contacts are traced, and no casual contacts are traced, and that in most cases the ability to trace 1–5 individuals per day per index case is sufficient. If smallpox is assumed to be transmitted very quickly to contacts, it may at times escape containment by ring vaccination, but could be controlled in these circumstances by mass vaccination. Conclusions Small introductions of smallpox are likely to be easily contained by ring vaccination, provided contact tracing is feasible. Uncertainties in the nature of bioterrorist smallpox (infectiousness, vaccine efficacy) support continued planning for ring vaccination as well as mass vaccination. If initiated, ring vaccination should be conducted without delays in vaccination, should include contacts of contacts (whenever there is sufficient capacity) and should be accompanied by increased public awareness and surveillance.
Collapse
Affiliation(s)
- Travis C Porco
- San Francisco Department of Public Health, Community Health and Epidemiology Section, Epidemiology and Effectiveness Research Unit, 101 Grove Street Suite 204, San Francisco, California 94102 USA
- Center for Infectious Disease Preparedness, School of Public Health, University of California, Berkeley, USA
- Surveillance and Epidemiology Section, Tuberculosis Control Branch, Division of Communicable Disease Control, California Department of Health Services, Berkeley, California, USA
| | - Karen A Holbrook
- San Francisco Department of Public Health, Community Health and Epidemiology Section, Epidemiology and Effectiveness Research Unit, 101 Grove Street Suite 204, San Francisco, California 94102 USA
| | - Susan E Fernyak
- San Francisco Department of Public Health, Community Health and Epidemiology Section, Epidemiology and Effectiveness Research Unit, 101 Grove Street Suite 204, San Francisco, California 94102 USA
| | - Diane L Portnoy
- San Francisco Department of Public Health, Community Health and Epidemiology Section, Epidemiology and Effectiveness Research Unit, 101 Grove Street Suite 204, San Francisco, California 94102 USA
| | - Randy Reiter
- San Francisco Department of Public Health, Community Health and Epidemiology Section, Epidemiology and Effectiveness Research Unit, 101 Grove Street Suite 204, San Francisco, California 94102 USA
| | - Tomás J Aragón
- San Francisco Department of Public Health, Community Health and Epidemiology Section, Epidemiology and Effectiveness Research Unit, 101 Grove Street Suite 204, San Francisco, California 94102 USA
- Center for Infectious Disease Preparedness, School of Public Health, University of California, Berkeley, USA
| |
Collapse
|
7
|
Abstract
The need for a planned response to a deliberate introduction of smallpox has recently become urgent. We constructed a stochastic simulator of the spread of smallpox in structured communities to compare the effectiveness of mass vaccination versus targeted vaccination of close contacts of cases. Mass vaccination before smallpox introduction or immediately after the first cases was more effective than targeted vaccination in preventing and containing epidemics if there was no prior herd immunity (that is, no prior immunologic protection within the population). The effectiveness of postrelease targeted and mass vaccinations increased if we assumed that there was residual immunity in adults vaccinated before 1972, but the effectiveness of targeted vaccination increased more than that of mass vaccination. Under all scenarios, targeted vaccination prevented more cases per dose of vaccine than did mass vaccination. Although further research with larger-scale structured models is needed, our results suggest that increasing herd immunity, perhaps with a combination of preemptive voluntary vaccination and vaccination of first responders, could enhance the effectiveness of postattack intervention. It could also help targeted vaccination be more competitive with mass vaccination at both preventing and containing a deliberate introduction of smallpox.
Collapse
Affiliation(s)
- M Elizabeth Halloran
- Department of Biostatistics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
| | | | | | | |
Collapse
|
8
|
Abstract
The eradication of smallpox was achieved by surveillance and containment vaccination after the failure of mass immunization campaigns. The reasons for this failure are considered in this paper. Comparison of population densities in the Indian subcontinent and Africa show that in highly populated areas even an 80% vaccine coverage will still leave a density of susceptibles high enough to maintain the disease, a finding with important implications for other vaccine campaigns.
Collapse
|
9
|
Abstract
Measles shows three distinct transmission patterns in the tropics, one each in urban, rural and insular or very remote areas. The characteristics of measles transmission are reviewed for each area, both with and without immunization. Planning must be based on the best use of currently underused infrastructure in the light of epidemiology. Mass mobile campaigns are not advised for urban areas. Vaccination of the sick and the well as part of episodic medical care is proposed, and vaccination of the sick is supported as safe and effective. Age floors and ceilings should be set with reference to the local situation; adoption of international "rules of thumb", without reference to local conditions, is inadvisable." A mixed strategy is urged for rural areas, with routine immunization against measles as part of a multi-antigen programme. Routine immunization should be complemented by annual surveillance and containment during the seasonal trough. Research and development needs in measles control include better understanding of measles epidemiology, more operationally useful quantitative models, and trials of new control strategies. Control, elimination and eradication are defined and discussed.
Collapse
|