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Steffen R, Chen LH, Leggat PA. Travel vaccines-priorities determined by incidence and impact. J Travel Med 2023; 30:taad085. [PMID: 37341307 DOI: 10.1093/jtm/taad085] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/22/2023]
Abstract
BACKGROUND Infectious disease epidemiology is continuously shifting. While travel has been disrupted by the COVID-19 pandemic and travel-related epidemiological research experienced a pause, further shifts in vaccine-preventable diseases (VPDs) relevant for travellers have occurred. METHODS We conducted a literature search on the epidemiology of travel-related VPD and synthesized data for each disease with a focus on symptomatic cases and on the impact of the respective infection among travellers, considering the hospitalization rate, disease sequela and case fatality rate. We present new data and revised best estimates on the burden of VPD relevant for decisions on priorities in travel vaccines. RESULTS COVID-19 has emerged to be a top travel-related risk and influenza remains high in the ranking with an estimated incidence at 1% per month of travel. Dengue is another commonly encountered infection among international travellers with estimated monthly incidence of 0.5-0.8% among non-immune exposed travellers; the hospitalized proportion was 10 and 22%, respectively, according to two recent publications. With recent yellow fever outbreaks particularly in Brazil, its estimated monthly incidence has risen to >0.1%. Meanwhile, improvements in hygiene and sanitation have led to some decrease in foodborne illnesses; however, hepatitis A monthly incidence remains substantial in most developing regions (0.001-0.01%) and typhoid remains particularly high in South Asia (>0.01%). Mpox, a newly emerged disease that demonstrated worldwide spread through mass gathering and travel, cannot be quantified regarding its travel-related risk. CONCLUSION The data summarized may provide a tool for travel health professionals to prioritize preventive strategies for their clients against VPD. Updated assessments on incidence and impact are ever more important since new vaccines with travel indications (e.g. dengue) have been licensed or are undergoing regulatory review.
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Affiliation(s)
- Robert Steffen
- Epidemiology, Biostatistics and Prevention Institute, Department of Public and Global Health, Division of Infectious Diseases, World Health Organization Collaborating Centre for Travelers' Health, University of Zurich, Zurich 8001, Switzerland
- Division of Epidemiology, Human Genetics & Environmental Sciences, University of Texas School of Public Health, Houston, TX 77030, USA
| | - Lin H Chen
- Division of Infectious Diseases and Travel Medicine, Mount Auburn Hospital, Cambridge, MA 02138, USA
- Faculty of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Peter A Leggat
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4810, Australia
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa
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Harish V, Buajitti E, Burrows H, Posen J, Bogoch II, Corbeil A, Gubbay JB, Rosella LC, Morris SK. Geographic clustering of travel-acquired infections in Ontario, Canada, 2008-2020. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0001608. [PMID: 36963058 PMCID: PMC10022755 DOI: 10.1371/journal.pgph.0001608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/20/2023] [Indexed: 03/19/2023]
Abstract
As the frequency of international travel increases, more individuals are at risk of travel-acquired infections (TAIs). In this ecological study of over 170,000 unique tests from Public Health Ontario's laboratory, we reviewed all laboratory-reported cases of malaria, dengue, chikungunya, and enteric fever in Ontario, Canada between 2008-2020 to identify high-resolution geographical clusters for potential targeted pre-travel prevention. Smoothed standardized incidence ratios (SIRs) and 95% posterior credible intervals (CIs) were estimated using a spatial Bayesian hierarchical model. High- and low-incidence areas were described using data from the 2016 Census based on the home forward sortation area of patients testing positive. A second model was used to estimate the association between drivetime to the nearest travel clinic and incidence of TAI within high-incidence areas. There were 6,114 microbiologically confirmed TAIs across Ontario over the study period. There was spatial clustering of TAIs (Moran's I = 0.59, p<0.0001). Compared to low-incidence areas, high-incidence areas had higher proportions of immigrants (p<0.0001), were lower income (p = 0.0027), had higher levels of university education (p<0.0001), and less knowledge of English/French languages (p<0.0001). In the high-incidence Greater Toronto Area (GTA), each minute increase in drive time to the closest travel clinic was associated with a 3% reduction in TAI incidence (95% CI 1-6%). While urban neighbourhoods in the GTA had the highest burden of TAIs, geographic proximity to a travel clinic in the GTA was not associated with an area-level incidence reduction in TAI. This suggests other barriers to seeking and adhering to pre-travel advice.
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Affiliation(s)
- Vinyas Harish
- MD/PhD Program, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Emmalin Buajitti
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
| | - Holly Burrows
- Yale School of Public Health, Yale University, New Haven, CT, United States of America
| | - Joshua Posen
- Division of Infectious Diseases, The Hospital for Sick Children, Toronto, ON, Canada
| | - Isaac I. Bogoch
- Division of Infectious Diseases, Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | | | - Jonathan B. Gubbay
- Division of Infectious Diseases, The Hospital for Sick Children, Toronto, ON, Canada
- Public Health Ontario, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Laura C. Rosella
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Institute for Better Health, Trillium Health Partners, Mississauga, ON, Canada
| | - Shaun K. Morris
- Division of Infectious Diseases, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, ON, Canada
- * E-mail:
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Marasinghe DH, Cheaveau J, Meatherall B, Kuhn S, Vaughan S, Zimmer R, Pillai DR. Risk of malaria associated with travel to malaria-endemic areas to visit friends and relatives: a population-based case-control study. CMAJ Open 2020; 8:E60-E68. [PMID: 31992561 PMCID: PMC6996033 DOI: 10.9778/cmajo.20190070] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Reports relying on population-based data and using epidemiologic methodologies such as case-control study designs for malaria in travellers and multivariable regression analysis of risk factors are rare. The aim of this study was to investigate the epidemiologic characteristics of travellers who tested positive for malaria after visiting friends and relatives in malaria-endemic areas to determine the risk of malaria associated with such travel. METHODS Using routinely collected data from a population-based laboratory database, we conducted a case-control study of symptomatic people returning from travel to malaria-endemic areas who presented for malaria testing in Calgary from 2013 to 2017. We used a multivariable logistic regression to analyze the association between the presence of malaria and other risk factors. RESULTS There were 251 confirmed malaria cases during the study period, of which 219 were matched to 1129 returning travellers without malaria. Based on the multivariable regression, the odds of a traveller who visited friends and relatives in malariaendemic areas being diagnosed with malaria was 2.82 (95% confidence interval [CI] 1.42-5.92) times greater than that of other travellers to these regions. Adults (odds ratio [OR] 3.62, 95% CI 1.66-8.84), males (OR 2.70, 95% CI 1.56-4.80), travellers to Africa (OR 11.52, 95% CI 6.33-22.05) and those who did not seek pretravel advice (OR 0.38, 95% CI 0.20-0.70) were more likely to be diagnosed with malaria. Although those travelling to visit friends and relatives tended to stay longer in endemic areas than other travellers, visit duration was not associated with an increased likelihood of malaria in the model. The annual incidence of malaria was highest (13.34 per 100 000) in metropolitan wards associated with lower socioeconomic status and immigrant communities. INTERPRETATION Travellers who visited friends and relatives in malaria-endemic areas were less likely than other travellers to these regions to seek pretravel advice, take prophylaxis and have a visit duration less than 2 weeks; travelling to Africa and being male increased the odds of being diagnosed with malaria, independent of other factors. These data suggest that targeted strategies to provide pretravel care to travellers who visit friends and relatives in malaria-endemic areas may aid in reducing the burden of malaria in this population.
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Affiliation(s)
- Dewdunee H Marasinghe
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta
| | - James Cheaveau
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta
| | - Bonnie Meatherall
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta
| | - Susan Kuhn
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta
| | - Stephen Vaughan
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta
| | - Rudolf Zimmer
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta
| | - Dylan R Pillai
- Department of Epidemiology, Biostatistics and Occupational Health (Marasinghe), McGill University, Montréal, Que.; Departments of Microbiology, Immunology and Infectious Diseases (Cheaveau, Pillai), Medicine (Meatherall, Vaughan, Pillai), Pediatrics (Kuhn), Community Health Sciences (Zimmer, Pillai) and Pathology and Laboratory Medicine (Pillai), University of Calgary, Calgary, Alta.
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