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Xia Y, Caya C, Morin V, Singh AE, Serhir B, Libman M, Goldfarb DM, Wong T, Xiu F, Bélanger R, Touchette JS, Yansouni CP, Maheu-Giroux M. The population-level impact of introducing rapid diagnostic tests on syphilis transmission in Canadian arctic communities - a mathematical modeling study. LANCET REGIONAL HEALTH. AMERICAS 2024; 37:100845. [PMID: 39100242 PMCID: PMC11295708 DOI: 10.1016/j.lana.2024.100845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/27/2024] [Accepted: 07/09/2024] [Indexed: 08/06/2024]
Abstract
Background Canadian Arctic communities have experienced sustained syphilis transmission, with diagnoses rates 18-times higher than the national average. Remoteness from laboratory facilities leads to delays between syphilis screening and treatment, contributing to onward transmission. Rapid diagnostic tests can eliminate treatment delays via testing at the point-of-care. This study aims to describe syphilis diagnostic gaps and to estimate the impact of introducing rapid diagnostic tests at the point-of-care on syphilis transmission. Methods To assess the population-level impact of deploying rapid diagnostic tests, an individual-based model was developed using detailed surveillance data, population surveys, and a prospective diagnostic accuracy field study. The model was calibrated to syphilis diagnoses (2017-2022) from a community of approximately 1,050 sexually active individuals. The impacts of implementing rapid diagnostic tests using whole blood (sensitivity: 92% for infectious and 81% for non-infectious syphilis; specificity: 99%) from 2023 onward was calculated using the annual median fraction of cumulative new syphilis infections averted over 2023-2032. Findings The median modeled syphilis incidence among sexually active individuals was 44 per 1,000 in 2023. Males aged 16-30 years exhibited a 51% lower testing rate than that of their female counterparts. Maintaining all interventions constant at their 2022 levels, implementing rapid diagnostic tests could avert a cumulative 33% (90% credible intervals: 18-43%) and 37% (21-46%) of new syphilis infections over 5 and 10 years, respectively. Increasing testing rates and contact tracing may enhance the effect of rapid diagnostic tests. Interpretation Implementing rapid diagnostic tests for syphilis in Arctic communities could reduce infections and enhance control of epidemics. Such effective diagnostic tools could enable rapid outbreak responses by providing same-day testing and treatment at the point-of-care. Funding Canadian Institutes of Health Research.
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Affiliation(s)
- Yiqing Xia
- Department of Epidemiology and Biostatistics, School of Population and Global Health, McGill University, Montréal, Québec, Canada
| | - Chelsea Caya
- Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montréal, Québec, Canada
| | - Véronique Morin
- Nunavik Regional Board of Health and Social Services, Kuujjuaq, Québec, Canada
| | - Ameeta E. Singh
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Bouchra Serhir
- Laboratoire de Santé Publique du Québec/Institut National de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Québec, Canada
| | - Michael Libman
- JD MacLean Centre for Tropical Diseases, McGill University Health Centre, Montréal, Québec, Canada
- Divisions of Infectious Diseases and Medical Microbiology, McGill University Health Centre, Montréal, Québec, Canada
| | - David M. Goldfarb
- BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tom Wong
- Indigenous Services Canada, Government of Canada, Ottawa, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Fanyu Xiu
- Department of Epidemiology and Biostatistics, School of Population and Global Health, McGill University, Montréal, Québec, Canada
| | - Richard Bélanger
- Département de Pédiatrie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Jean-Sébastien Touchette
- Department of Public Health, Nunavik Regional Board of Health and Social Services, Québec, Canada
| | - Cédric P. Yansouni
- Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montréal, Québec, Canada
- JD MacLean Centre for Tropical Diseases, McGill University Health Centre, Montréal, Québec, Canada
- Divisions of Infectious Diseases and Medical Microbiology, McGill University Health Centre, Montréal, Québec, Canada
| | - Mathieu Maheu-Giroux
- Department of Epidemiology and Biostatistics, School of Population and Global Health, McGill University, Montréal, Québec, Canada
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Caya C, Maheu-Giroux M, Xia Y, Serhir B, Morin V, Libman M, Corsini R, Goldfarb DM, Wong T, Singh AE, Yansouni CP. Stopping syphilis transmission in Arctic communities through rapid diagnostic testing: The STAR study protocol. PLoS One 2022; 17:e0273713. [PMID: 36094912 PMCID: PMC9467359 DOI: 10.1371/journal.pone.0273713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/11/2022] [Indexed: 11/18/2022] Open
Abstract
Background Intense transmission of syphilis has emerged in some Canadian Arctic communities despite screening and prevention efforts. The remoteness of most communities and limited diagnostic infrastructure yield long delays (≥14 days) between screening and treatment of cases. These hamper syphilis control efforts and may contribute to sustained transmission. Syphilis rapid diagnostic tests (RDTs) have been developed to make screening more accessible and to inform clinical decision-making within the same clinical encounter. These RDTs have been successfully deployed in several countries, but not yet in Canada. Methods and design We describe the methodology of the “Stopping Syphilis Transmission in Arctic Communities Through Rapid Diagnostic Testing” (STAR) study, wherein the clinical and epidemiological impact of deploying a dual syphilis RDT in the context of ongoing transmission in Nunavut and Nunavik will be evaluated. In this prospective multisite field evaluation, sexually active individuals aged ≥14 years at risk for syphilis will be offered screening by an RDT at the point-of-care by non-laboratory trained registered nurses. Whole blood and serum specimens will be concurrently collected, when feasible, for rapid testing with an RDT containing both treponemal and non-treponemal components (Chembio DPP®Syphilis Screen & Confirm) and compared to laboratory-based reference testing according to a reverse sequence algorithm. The diagnostic accuracy of the RDT, using both whole blood and centrifuged serum specimens, will be validated under real-world conditions in remote Northern settings, outside of specialized laboratories. Additionally, screening-to-treatment time, case detection rates, and the number of infectious contacts averted by using the RDT relative to reference testing will be estimated. The impact of both diagnostic approaches on syphilis transmission dynamics will also be modeled. Discussion This study will provide much needed evidence for strengthening rapid responses to emerging syphilis outbreaks in remote Arctic regions, by supplementing traditional diagnostic strategies with an RDT to rapidly triage patients likely in need of treatment. These results will also inform the development and tailoring of future diagnostic strategies and public health responses to emerging outbreaks in the North.
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Affiliation(s)
- Chelsea Caya
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, Quebec, Canada
| | - Mathieu Maheu-Giroux
- Department of Epidemiology, Biostatistics and Occupational Health, School of Population and Global Health, McGill University, Montreal, Quebec, Canada
| | - Yiqing Xia
- Department of Epidemiology, Biostatistics and Occupational Health, School of Population and Global Health, McGill University, Montreal, Quebec, Canada
| | - Bouchra Serhir
- Laboratoire de Santé Publique du Québec /Institut National de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Veronique Morin
- Nunavik Regional Board of Health and Social Services, Kuujjuaq, Quebec, Canada
| | - Michael Libman
- JD MacLean Centre for Tropical Diseases, McGill University Health Centre, Montreal, Quebec, Canada
- Divisions of Infectious Diseases and Medical Microbiology, McGill University Health Centre, Montreal, Quebec, Canada
| | - Rachel Corsini
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, Quebec, Canada
| | - David M. Goldfarb
- BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tom Wong
- Indigenous Services Canada, Government of Canada, Ottawa, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Ameeta E. Singh
- Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Cedric P. Yansouni
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- McGill Interdisciplinary Initiative in Infection and Immunity, Montreal, Quebec, Canada
- JD MacLean Centre for Tropical Diseases, McGill University Health Centre, Montreal, Quebec, Canada
- Divisions of Infectious Diseases and Medical Microbiology, McGill University Health Centre, Montreal, Quebec, Canada
- * E-mail:
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