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Hu Y, Zhao R, Li G, Liu Y, Lu F, She B, Zhao M, Zhang L. Associations between antibacterial mouthwash use with sexual behaviours and sexually transmitted infections among Chinese men who have sex with men: a cross-sectional study. Sex Health 2024; 21:SH24083. [PMID: 39159291 DOI: 10.1071/sh24083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 07/30/2024] [Indexed: 08/21/2024]
Abstract
Background Mouthwash is a commonly used product with the potential to prevent STIs. This study aimed to determine the association between mouthwash use frequency with sexual behaviours and STIs among Chinese men who have sex with men (MSM). Methods A cross-sectional study was conducted among MSM in Xi'an, China, from January to September 2022. Participants were categorised into non-mouthwash users, occasional (used it less than once every week) and frequent (used it more than once every week) mouthwash users. Multinomial logistic regression was performed to identify the association between mouthwash use frequency with sexual behaviours. Results Of 838 MSM included in the analysis, 621 (74.11%) reported never using mouthwash, whereas 47 (5.60%) used it occasionally and 170 (20.29%) used it frequently. Frequent mouthwash users had a lower prevalence of chlamydia compared with occasional users (8.33% vs 23.93%, P Conclusion MSM with more sexual partners or lower condom use frequency were more likely to be frequent mouthwash users. However, frequent mouthwash users had a lower chlamydia prevalence.
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Affiliation(s)
- Yawu Hu
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China
| | - Rui Zhao
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China
| | - Gaixia Li
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China
| | - Yi Liu
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China
| | - Fang Lu
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China
| | - Bingyang She
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China
| | - Min Zhao
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China; and Department of Infectious Diseases, The Second Affiliated Hospital of Xi'an Jiaotong University, 157 Xiwu Av, Xi'an 710004, Shaanxi, China
| | - Lei Zhang
- China-Australia Joint Research Centre for Infectious Diseases, School of Public Health, Xi'an Jiaotong University Health Science Centre, 76 Yanta West Road, Xi'an 710061, Shaanxi, China; and Artificial Intelligence and Modelling in Epidemiology Program, Melbourne Sexual Health Centre, Alfred Health, Melbourne, Vic, Australia; and School of Translational Medicine, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Vic, Australia
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2
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Ye R, Lai Y, Gu J. New sexually transmitted HIV infections from 2016 to 2050 in Guangdong Province, China: a study based on a dynamic compartmental model. BMC Public Health 2024; 24:1307. [PMID: 38745217 PMCID: PMC11092022 DOI: 10.1186/s12889-024-18735-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 04/29/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND In Guangdong Province, China, there is lack of information on the HIV epidemic among high-risk groups and the general population, particularly in relation to sexual transmission, which is a predominant route. The new HIV infections each year is also uncertain owing to HIV transmission from men who have sex with men (MSM) to women, as a substantial proportion of MSM also have female sexual partnerships to comply with social demands in China. METHODS A deterministic compartmental model was developed to predict new HIV infections in four risk groups, including heterosexual men and women and low- and high-risk MSM, in Guangdong Province from 2016 to 2050, considering HIV transmission from MSM to women. The new HIV infections and its 95% credible interval (CrI) were predicted. An adaptive sequential Monte Carlo method for approximate Bayesian computation (ABC-SMC) was used to estimate the unknown parameter, a mixing index. We calibrated our results based on new HIV diagnoses and proportions of late diagnoses. The Morris and Sobol methods were applied in the sensitivity analysis. RESULTS New HIV infections increased during and 2 years after the COVID-19 pandemic, then declined until 2050. New infections rose from 8,828 [95% credible interval (CrI): 6,435-10,451] in 2016 to 9,652 (95% CrI: 7,027-11,434) in 2019, peaking at 11,152 (95% CrI: 8,337-13,062) in 2024 before declining to 7,084 (95% CrI: 5,165-8,385) in 2035 and 4,849 (95% CrI: 3,524-5,747) in 2050. Women accounted for approximately 25.0% of new HIV infections, MSM accounted for 40.0% (approximately 55.0% of men), and high-risk MSM accounted for approximately 25.0% of the total. The ABC-SMC mixing index was 0.504 (95% CrI: 0.239-0.894). CONCLUSIONS Given that new HIV infections and the proportion of women were relatively high in our calibrated model, to some extent, the HIV epidemic in Guangdong Province remains serious, and services for HIV prevention and control are urgently needed to return to the levels before the COVID-19 epidemic, especially in promoting condom-based safe sex and increasing awareness of HIV prevention to general population.
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Affiliation(s)
- Rong Ye
- Department of Medical Statistics, School of Public Health, Sun Yat-sen University, No. 74 Zhongshan 2nd Road, Guangzhou, 510080, China
| | - Yingsi Lai
- Department of Medical Statistics, School of Public Health, Sun Yat-sen University, No. 74 Zhongshan 2nd Road, Guangzhou, 510080, China
- Sun Yat-sen Global Health institute, Sun Yat-sen University, Guangzhou, China
| | - Jing Gu
- Department of Medical Statistics, School of Public Health, Sun Yat-sen University, No. 74 Zhongshan 2nd Road, Guangzhou, 510080, China.
- Sun Yat-sen Global Health institute, Sun Yat-sen University, Guangzhou, China.
- Research Center of Health Informatics, Sun Yat-sen University, Guangzhou, China.
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Tsoumanis A, Vanden Berghe W, Hens N, Van Dijck C. Estimating Partnership Duration among MSM in Belgium-A Modeling Study. Infect Dis Rep 2024; 16:435-447. [PMID: 38804442 PMCID: PMC11130929 DOI: 10.3390/idr16030032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/18/2024] [Accepted: 04/26/2024] [Indexed: 05/29/2024] Open
Abstract
Mathematical modeling is widely used for describing infection transmission and evaluating interventions. The lack of reliable social parameters in the literature has been mentioned by many modeling studies, leading to limitations in the validity and interpretation of the results. Using data from the European MSM Internet survey 2017, we developed a network model to describe sex acts among MSM in Belgium. The model simulates daily sex acts among steady, persistent casual and one-off partners in a population of 10,000 MSM, grouped as low- or high-activity by using three different definitions. Model calibration was used to estimate partnership duration and homophily rates to match the distribution of cumulative sex partners over 12 months. We estimated an average duration between 1065 and 1409 days for steady partnerships, 4-6 and 251-299 days for assortative high- and low-activity individuals and 8-13 days for disassortative persistent casual partnerships, respectively, varying across the three definitions. High-quality data on social network and behavioral parameters are scarce in the literature. Our study addresses this lack of information by providing a method to estimate crucial parameters for network specification.
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Affiliation(s)
- Achilleas Tsoumanis
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Nationalestraat 155, 2000 Antwerp, Belgium; (W.V.B.)
- Centre for Health Economics Research and Modelling Infectious Diseases (CHERMID), Vaccine and Infectious Disease Institute (VAXINFECTIO), University of Antwerp, 2610 Antwerp, Belgium;
| | - Wim Vanden Berghe
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Nationalestraat 155, 2000 Antwerp, Belgium; (W.V.B.)
| | - Niel Hens
- Centre for Health Economics Research and Modelling Infectious Diseases (CHERMID), Vaccine and Infectious Disease Institute (VAXINFECTIO), University of Antwerp, 2610 Antwerp, Belgium;
- Interuniversity Institute for Biostatistics and Statistical Bioinformatics, Data Science Institute, Hasselt University, 3590 Diepenbeek, Belgium
| | - Christophe Van Dijck
- Department of Clinical Sciences, Institute of Tropical Medicine Antwerp, Nationalestraat 155, 2000 Antwerp, Belgium; (W.V.B.)
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Elder H, Platt L, Leach D, Sheetoh C, Ramirez VM, Molotnikov L, Hernandez B, Roosevelt K, Hsu KK. Factors Associated With Delays in Presentation and Treatment of Gonorrhea, Massachusetts 2015-2019. Sex Transm Dis 2024; 51:146-155. [PMID: 38133572 PMCID: PMC10922616 DOI: 10.1097/olq.0000000000001917] [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] [Indexed: 12/23/2023]
Abstract
BACKGROUND Rates of gonorrhea are increasing across the United States. Understanding and addressing contributing factors associated with longer time to diagnosis and treatment may shorten the duration of infectiousness, which in turn may limit transmission. METHODS We used Massachusetts data from the US Centers for Disease Control and Prevention Sexually Transmitted Disease Surveillance Network collected between July 2015 and September 2019, along with routinely reported surveillance data, to assess time from gonorrhea symptom onset to presentation to care, and time from presentation to care to receipt of treatment. Factors associated with longer time to presentation (TTP) and time to treatment (TTT) were assessed using Cox proportional hazard models with a constant time variable. RESULTS Among symptomatic patients (n = 672), 31% did not receive medical care within 7 days of symptom onset. Longer TTP was associated with younger age, female gender, reporting cost as a barrier to care, and provider report of proctitis. Among patients with symptoms and/or known contact to gonorrhea (n = 827), 42% did not receive presumptive treatment. Longer TTT was associated with female gender, non-Hispanic other race/ethnicity, and clinics with less gonorrhea treatment experience. Among asymptomatic patients without known exposure to STI (n = 235), 26% did not receive treatment within 7 days. Longer TTT was associated with sexually transmitted disease clinic/family planning/reproductive health clinics and a test turnaround time of ≥3 days. CONCLUSIONS Delays in presentation to care and receipt of treatment for gonorrhea are common. Factors associated with longer TTP and TTT highlight multiple opportunities for reducing the infectious period of patients with gonorrhea.
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Affiliation(s)
- Heather Elder
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Laura Platt
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, MA
| | - Dylan Leach
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Cordelia Sheetoh
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Victor M Ramirez
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Lauren Molotnikov
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Brenda Hernandez
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Kathleen Roosevelt
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
| | - Katherine K. Hsu
- Division of STD Prevention, Bureau of Infectious Disease and Laboratory Science, Massachusetts Department of Public Health, Jamaica Plain, MA
- Section of Pediatric Infectious Diseases, Boston University Medical Center, Boston, MA
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Asamoah JKK, Safianu B, Afrifa E, Obeng B, Seidu B, Wireko FA, Sun GQ. Optimal control dynamics of Gonorrhea in a structured population. Heliyon 2023; 9:e20531. [PMID: 37842629 PMCID: PMC10568113 DOI: 10.1016/j.heliyon.2023.e20531] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/07/2023] [Accepted: 09/28/2023] [Indexed: 10/17/2023] Open
Abstract
Gonorrhea is a serious global health problem due to its high incidence, with approximately 82.4 million new cases in 2020. To evaluate the consequences of targeted dynamic control of gonorrhea infection transmission, a model for gonorrhea with optimal control analysis is proposed for a structured population. The study looked at the model's positively invariant and bounded regions. The gonorrhea secondary infection expression, R 0 for the structured population is computed. The maximum principle of Pontryagin is utilised to construct the optimal system for the formulated mathematical model. To reduce the continuous propagation of gonorrhea, we incorporated education, condoms usage, vaccinations, and treatment as control strategies. The numerical simulations show that the number of infections decreases when the controls are implemented. The effectiveness of the controls is shown using the efficacy plots.
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Affiliation(s)
- Joshua Kiddy K. Asamoah
- School of Mathematics, North University of China, Taiyuan, Shanxi 030051, China
- Department of Mathematics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Beilawu Safianu
- Department of Mathematics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Emmanuel Afrifa
- Department of Mathematics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Benjamin Obeng
- Department of Mathematics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Baba Seidu
- Department of Mathematics, School of Mathematical Sciences, C. K. Tedam University of Technology and Applied Sciences, Navrongo, Ghana
| | - Fredrick Asenso Wireko
- Department of Mathematics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Gui-Quan Sun
- School of Mathematics, North University of China, Taiyuan, Shanxi 030051, China
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6
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Chesson HW, Bernstein KT, Barbee LA. Kiss Around and Find Out: Kissing as a Risk Factor for Pharyngeal Gonorrhea. Sex Transm Dis 2023; 50:402-403. [PMID: 37074310 PMCID: PMC11247368 DOI: 10.1097/olq.0000000000001816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Affiliation(s)
- Harrell W. Chesson
- Division of STD Prevention, National Center for HIV, Viral Hepatitis, STD, and TB Prevention, Atlanta, GA
| | - Kyle T. Bernstein
- Division of Scientific Education and Professional Development, Center for Surveillance, Epidemiology, and Laboratory Services, Centers for Disease Control and Prevention, Atlanta, GA
| | - Lindley A. Barbee
- Division of STD Prevention, National Center for HIV, Viral Hepatitis, STD, and TB Prevention, Atlanta, GA
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Scangarella-Oman NE, Hossain M, Perry CR, Tiffany C, Powell M, Swift B, Dumont EF. Dose selection for a phase III study evaluating gepotidacin (GSK2140944) in the treatment of uncomplicated urogenital gonorrhoea. Sex Transm Infect 2023; 99:64-69. [PMID: 36411033 PMCID: PMC9887395 DOI: 10.1136/sextrans-2022-055518] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/30/2022] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Gepotidacin is a novel, first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action and is active against most strains of Neisseria gonorrhoeae (N. gonorrhoeae). Phase II data suggested higher exposures were needed for efficacy and to suppress resistance development. A translational approach using in vitro pharmacokinetic/pharmacodynamic (PK/PD) and clinical data was used to select a gepotidacin dose for a phase III study. In this narrative review of previously shown data, we summarise how a translational approach based on in vitro PK/PD and population PK modelling and simulation data was undertaken to select a dosing regimen for the ongoing phase III gepotidacin study in participants with uncomplicated urogenital gonorrhoea. METHODS For dose selection, prior in vitro minimum inhibitory concentrations (MICs) and PK/PD data were available. PK modelling was conducted to determine a dose that would limit plasma concentrations to less than 14 µg/mL (as concentrations above this are associated with QT prolongation and effects associated with acetylcholinesterase inhibition) while maintaining ≥90% probability of target attainment (PTA) for efficacy and resistance suppression against N. gonorrhoeae isolates with gepotidacin MICs ≤1 µg/mL. RESULTS Two 3000 mg gepotidacin doses, administered 10-12 hours apart, resulted in PTA of ≥97.5% and ≥91.7% for gepotidacin MICs ≤1 µg/mL for the ratio of the area under the free drug plasma concentration-time curve over 24 hours to the MIC (fAUC0-24/MIC) efficacy, and resistance suppression targets of 40 and 46, respectively, but limited the occurrence of maximum plasma concentrations ≥14 µg/mL. CONCLUSIONS Two gepotidacin 3000 mg oral doses 10-12 hours apart provide ~2-fold higher systemic exposures, increase efficacy for higher gepotidacin MIC N. gonorrhoeae isolates, reduce resistance potential and limit plasma concentrations of potential safety concern, compared with higher doses.
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Affiliation(s)
| | | | | | | | - Marcy Powell
- GSK, Research Triangle Park, North Carolina, USA
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8
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Kenyon C. Variations in sexual network connectivity may explain dramatic variations in sexually transmitted infection prevalence between populations and over time: a selected four-country analysis. F1000Res 2022; 9:1009. [PMID: 36246487 PMCID: PMC9490289 DOI: 10.12688/f1000research.24968.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
Background: The incidence of sexually transmitted infections (STIs) has been noted to vary dramatically between population groups and over time. Here, the hypothesis that changes in network connectivity underpin these changes is explored. Methods: The incidence/prevalence estimates of HIV, herpes simplex virus-2, syphilis, chlamydia, and gonorrhoea, as well as two markers of sexual network connectivity (partner concurrency and multiple partnering) by ethnic group and sexual orientation in Kenya, South Africa, the United Kingdom (UK) and the United States (USA) were extracted from published studies. Pearson’s correlation was used to test the association between the markers of network connectivity and the incidence/prevalence of these five STIs. A literature review was performed to evaluate the possible causes of the increases and decreases in syphilis incidence over the past 60 years. Results: In each country, the five STIs were found to cluster in particular ethnic groups and sexual orientations and to be positively associated with the two markers of network connectivity. Syphilis incidence in the UK and USA was found to increase dramatically in the 1960s/1970s, decline in the 1980s and again increase in the late 1990s. These changes took place predominantly in men who have sex with men, and were preceded by corresponding changes in network connectivity. The large decline in antenatal syphilis prevalence in Kenya and South Africa in the 1990s were likewise preceded by declines in network connectivity. Conclusions: Although other explanatory variables are not controlled for, the present analysis is compatible with the hypothesis that differential network connectivity is a parsimonious explanation for variations in STI incidence over time and between populations.
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Affiliation(s)
- Chris Kenyon
- HIV/STI Unit, Institute of Tropical Medicine, Antwerp, Antwerp, 2000, Belgium
- Division of Infectious Diseases and HIV Medicine, University of Cape Town, Cape Town, 7700, South Africa
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9
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Vegvari C, Grad YH, White PJ, Didelot X, Whittles LK, Scangarella-Oman NE, Mitrani-Gold FS, Dumont E, Perry CR, Gilchrist K, Hossain M, Mortimer TD, Anderson RM, Gardiner D. Using rapid point-of-care tests to inform antibiotic choice to mitigate drug resistance in gonorrhoea. ACTA ACUST UNITED AC 2021; 25. [PMID: 33124551 PMCID: PMC7596916 DOI: 10.2807/1560-7917.es.2020.25.43.1900210] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background The first cases of extensively drug resistant gonorrhoea were recorded in the United Kingdom in 2018. There is a public health need for strategies on how to deploy existing and novel antibiotics to minimise the risk of resistance development. As rapid point-of-care tests (POCTs) to predict susceptibility are coming to clinical use, coupling the introduction of an antibiotic with diagnostics that can slow resistance emergence may offer a novel paradigm for maximising antibiotic benefits. Gepotidacin is a novel antibiotic with known resistance and resistance-predisposing mutations. In particular, a mutation that confers resistance to ciprofloxacin acts as the ‘stepping-stone’ mutation to gepotidacin resistance. Aim To investigate how POCTs detecting Neisseria gonorrhoeae resistance mutations for ciprofloxacin and gepotidacin can be used to minimise the risk of resistance development to gepotidacin. Methods We use individual-based stochastic simulations to formally investigate the aim. Results The level of testing needed to reduce the risk of resistance development depends on the mutation rate under treatment and the prevalence of stepping-stone mutations. A POCT is most effective if the mutation rate under antibiotic treatment is no more than two orders of magnitude above the mutation rate without treatment and the prevalence of stepping-stone mutations is 1–13%. Conclusion Mutation frequencies and rates should be considered when estimating the POCT usage required to reduce the risk of resistance development in a given population. Molecular POCTs for resistance mutations and stepping-stone mutations to resistance are likely to become important tools in antibiotic stewardship.
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Affiliation(s)
- Carolin Vegvari
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Yonatan H Grad
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, United States.,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Peter J White
- Modelling and Economics Unit, National Infection Service, Public Health England, London, United Kingdom.,MRC Centre for Global Infectious Disease Analysis and NIHR Health Protection Research Unit in Modelling and Health Economics, School of Public Health, Imperial College London, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Xavier Didelot
- Current affiliation: School of Life Sciences and Department of Statistics, University of Warwick, United Kingdom.,MRC Centre for Global Infectious Disease Analysis and NIHR Health Protection Research Unit in Modelling and Health Economics, School of Public Health, Imperial College London, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Lilith K Whittles
- MRC Centre for Global Infectious Disease Analysis and NIHR Health Protection Research Unit in Modelling and Health Economics, School of Public Health, Imperial College London, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | | | | | - Etienne Dumont
- GlaxoSmithKline, Collegeville, Pennsylvania, United States
| | | | - Kim Gilchrist
- Current affiliation: Pfizer, Inc, Pennsylvania, United States.,GlaxoSmithKline, Collegeville, Pennsylvania, United States
| | | | - Tatum D Mortimer
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, United States
| | - Roy M Anderson
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - David Gardiner
- GlaxoSmithKline, Collegeville, Pennsylvania, United States
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10
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Kenyon C. To What Extent Should We Rely on Antibiotics to Reduce High Gonococcal Prevalence? Historical Insights from Mass-Meningococcal Campaigns. Pathogens 2020; 9:pathogens9020134. [PMID: 32085650 PMCID: PMC7168587 DOI: 10.3390/pathogens9020134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/06/2020] [Accepted: 02/17/2020] [Indexed: 12/22/2022] Open
Abstract
In the absence of a vaccine, current antibiotic-dependent efforts to reduce the prevalence of Neisseria gonorrhoeae in high prevalence populations have been shown to result in extremely high levels of antibiotic consumption. No randomized controlled trials have been conducted to validate this strategy and an important concern of this approach is that it may induce antimicrobial resistance. To contribute to this debate, we assessed if mass treatment in the related species, Neisseria meningitidis, was associated with the emergence of antimicrobial resistance. To this end, we conducted a historical review of the effect of mass meningococcal treatment programmes on the prevalence of N. meningitidis and the emergence of antimicrobial resistance. We found evidence that mass treatment programmes were associated with the emergence of antimicrobial resistance.
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Affiliation(s)
- Chris Kenyon
- HIV/STI Unit, Institute of Tropical Medicine, 2000 Antwerp, Belgium; ; Tel.: +32-3-2480796; Fax: +32-3-2480831
- Division of Infectious Diseases and HIV Medicine, University of Cape Town, Anzio Road, Observatory 7700, South Africa
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11
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Gsteiger S, Low N, Sonnenberg P, Mercer CH, Althaus CL. Gini coefficients for measuring the distribution of sexually transmitted infections among individuals with different levels of sexual activity. PeerJ 2020; 8:e8434. [PMID: 31998566 PMCID: PMC6977500 DOI: 10.7717/peerj.8434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/19/2019] [Indexed: 01/08/2023] Open
Abstract
Objectives Gini coefficients have been used to describe the distribution of Chlamydia trachomatis (CT) infections among individuals with different levels of sexual activity. The objectives of this study were to investigate Gini coefficients for different sexually transmitted infections (STIs), and to determine how STI control interventions might affect the Gini coefficient over time. Methods We used population-based data for sexually experienced women from two British National Surveys of Sexual Attitudes and Lifestyles (Natsal-2: 1999–2001; Natsal-3: 2010–2012) to calculate Gini coefficients for CT, Mycoplasma genitalium (MG), and human papillomavirus (HPV) types 6, 11, 16 and 18. We applied bootstrap methods to assess uncertainty and to compare Gini coefficients for different STIs. We then used a mathematical model of STI transmission to study how control interventions affect Gini coefficients. Results Gini coefficients for CT and MG were 0.33 (95% CI [0.18–0.49]) and 0.16 (95% CI [0.02–0.36]), respectively. The relatively small coefficient for MG suggests a longer infectious duration compared with CT. The coefficients for HPV types 6, 11, 16 and 18 ranged from 0.15 to 0.38. During the decade between Natsal-2 and Natsal-3, the Gini coefficient for CT did not change. The transmission model shows that higher STI treatment rates are expected to reduce prevalence and increase the Gini coefficient of STIs. In contrast, increased condom use reduces STI prevalence but does not affect the Gini coefficient. Conclusions Gini coefficients for STIs can help us to understand the distribution of STIs in the population, according to level of sexual activity, and could be used to inform STI prevention and treatment strategies.
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Affiliation(s)
- Sandro Gsteiger
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Nicola Low
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Pam Sonnenberg
- Institute for Global Health, University College London, London, UK
| | | | - Christian L Althaus
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
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Ayinde O, Tan W, Hepburn T, Ross JDC. Factors associated with time to presentation for individuals with symptomatic uncomplicated genital gonorrhoea: a cross sectional cohort study of GToG trial participants. Sex Transm Infect 2020; 96:251-257. [PMID: 31896736 DOI: 10.1136/sextrans-2019-054253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/29/2019] [Accepted: 12/12/2019] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES To determine the variation in the time from onset of symptoms to clinical presentation (time to presentation [TTP]) in a cohort of sexual health attendees with symptomatic uncomplicated genital gonorrhoea and to identify factors associated with TTP. METHODS Participants were recruited from 14 clinics across England into the 'Gentamicin for the Treatment of Gonorrhoea (GToG)' trial between October 2014 and November 2016. Multivariable analysis was performed using prospectively collected demographic, behavioural and clinical data in a subset of the GToG study cohort presenting with genital discharge and/or dysuria who tested positive for Neisseria gonorrhoeae using a nucleic acid amplification test. The results were expressed as geometric mean ratios (GMR) with 95% CI for time to presentation after onset of symptoms. RESULTS 316 participants (269 men and 47 women) with a median age of 27.6 years (IQR 23.0-34.8) were included. 194 (61%) were Caucasian, 29 (9%) Black African, 27 (9%) Asian and 66 (21%) of other ethnicities. Median TTP was 3 days for men (IQR 2-7) and 14 days for women (IQR 7-21). Participants reported genital discharge (297/316 [94%]), dysuria (251/316 [79%]), both genital discharge and dysuria (232/316 [73%]) and other concurrent symptoms 76/316 (24%) (e.g., rectal bleeding or genital itching). 45/316 (14%) participants reported sexual contact while symptomatic, of whom TTP was more than 7 days in 32/45 (71%). A longer TTP was associated with gender (female cf. male, GMR 2.34 [1.67 to 3.26]), no prior history of gonorrhoea (GMR 1.46 [1.15 to 1.86]), 'regular' or 'ex-regular' sexual relationship (regular cf. one off GMR 1.35 [1.05 to 1.72]); ex-regular cf. one off GMR 1.88 [1.12 to 3.14]), and being heterosexual (GMR 1.69 [1.31 to 2.19]). CONCLUSION Specific demographic and behavioural factors are associated with a longer TTP in individuals with symptomatic genital gonorrhoea. Detailed knowledge of these factors can be used to prioritise and optimise gonorrhoea management and prevention.
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Affiliation(s)
- Oluseyi Ayinde
- Department of Sexual Health and HIV, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Wei Tan
- Nottingham Clinical Trials Unit, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Trish Hepburn
- Nottingham Clinical Trials Unit, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Jonathan D C Ross
- Department of Sexual Health and HIV, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
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Tuite AR, Rönn MM, Wolf EE, Gift TL, Chesson HW, Berruti A, Galer K, Menzies NA, Hsu K, Salomon JA. Estimated Impact of Screening on Gonorrhea Epidemiology in the United States: Insights From a Mathematical Model. Sex Transm Dis 2019; 45:713-722. [PMID: 29894368 PMCID: PMC6813831 DOI: 10.1097/olq.0000000000000876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The burden of gonorrhea infections in the United States is high. There are marked disparities by race/ethnicity and sexual orientation. We quantified the impact of screening and treatment on gonorrhea rates in the US population aged 15 to 39 years for the period 2000 to 2015 and estimated the impact that alternative screening strategies might have had over the same period. METHODS We developed a national-level transmission model that divides the population by race/ethnicity, preferred gender of sex partners, age, gender, and sexual activity level. We compared our fitted model ("base case") to 4 alternative strategies: (i) no screening, (ii) full adherence to current screening guidelines, (iii) annual universal screening, or (iv) enhanced screening in groups with the highest infection burden. Main outcomes were incidence, infections averted, and incidence rate ratios by race/ethnicity. Mean values and 95% credible intervals were calculated from 1000 draws from parameter posterior distributions. RESULTS The calibrated model reproduced observed trends in gonorrhea, including disparities in infection burden by race/ethnicity. We estimated that screening for gonorrhea from 2000 to 2015 averted 30% (95% credible intervals, 18-44%) of total infections that would otherwise have occurred. All alternative active screening strategies were estimated to further reduce, but not eliminate, gonorrhea infections relative to the base case, with differential impacts on the subpopulations of interest. CONCLUSIONS Our model results suggest that screening has reduced gonorrhea incidence in the US population. Additional reductions in infection burden may have been possible over this period with increased screening, but elimination was unlikely.
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Affiliation(s)
| | | | | | - Thomas L Gift
- Centers for Disease Control and Prevention, Atlanta, GA
| | | | | | | | | | - Katherine Hsu
- Massachusetts Department of Public Health, Boston, MA
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Economic Assessment of Reverse Algorithm Syphilis Screening in a High Prevalence Population. Sex Transm Dis 2019; 45:834-841. [PMID: 29870503 DOI: 10.1097/olq.0000000000000875] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND More laboratories are screening for syphilis with automated treponemal immunoassays. We compared direct costs and downstream consequences when a local public health laboratory switches from a traditional algorithm (nontreponemal screening) to a reverse algorithm (treponemal screening). METHODS We created a decision analysis model based on laboratory and surveillance data to estimate the cost-effectiveness of a reverse syphilis-screening algorithm from the perspectives of the Los Angeles County Public Health Laboratory and the Los Angeles County Department of Public Health (laboratory + STD Program costs) in 2015 US dollars. RESULTS The estimated total costs for the Department (Public Health Laboratories) were $2,153,225 ($367,119) for the traditional algorithm and $2,197,478 ($239,855) for the reverse algorithm. Reverse algorithm screening was estimated to detect an additional 626 cases of syphilis, 9.7% more than the traditional algorithm. The incremental cost-effectiveness ratio for the reverse algorithm from the Public Health Department's perspective was $39 per additional syphilis case detected. Cost of follow-up, screening test costs, positivity rates, and frequency of repeat infections most affected the cost-effectiveness of reverse algorithm. Costs were significantly higher for the reverse algorithm when the enzyme Immunoassay/chemiluminescence immunoassay screening test cost was the same as the published Centers for Medicaid Services treponemal test cost. CONCLUSIONS Using the reverse algorithm would have been slightly more expensive for the Los Angeles County Department of Public Health, but would have identified more syphilis cases and would have resulted in lower laboratory costs.
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15
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Fairley CK, Cornelisse VJ, Hocking JS, Chow EPF. Models of gonorrhoea transmission from the mouth and saliva. THE LANCET. INFECTIOUS DISEASES 2019; 19:e360-e366. [PMID: 31324517 DOI: 10.1016/s1473-3099(19)30304-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/22/2019] [Accepted: 04/16/2019] [Indexed: 11/28/2022]
Abstract
This Personal View argues for a new framework of gonorrhoea transmission in men who have sex with men in which the oropharynx plays a major role in transmitting gonorrhoea to, or acquiring gonorrhoea from, their partner's oropharynx, penis, or anorectum through either direct contact or via saliva. To avoid preconceived notions of transmission dynamics, we ask readers to imagine that they are investigating a new sexually transmitted infection. On the basis of the existing clinical and epidemiological data for gonorrhoea at the penis, oropharynx, and anorectum site, we develop two models for transmission: the so-called penile model and the so-called oropharyngeal model. We argue that the existing epidemiological data and behavioural data best fit the oropharyngeal model. Our argument rests on the observation that, at the population level, the prevalence of urethral gonorrhoea is too rare to explain the high incidence of oropharynx and anorectum infection. We describe studies of gonorrhoea detection in saliva, saliva use during sex, epidemiological studies of kissing and oropharyngeal gonorrhoea, as well as studies aided by mathematical models. Finally, we argue that the correlation between sexual acts (eg, kissing, oral sex, anal sex, and saliva use) is so high that any epidemiological study that does not measure these factors will be prone to confounding.
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Affiliation(s)
- Christopher K Fairley
- Melbourne Sexual Health Centre, Alfred Health, Carlton, VIC, Australia; Central Clinical School, Monash University, Melbourne, VIC, Australia.
| | - Vincent J Cornelisse
- Melbourne Sexual Health Centre, Alfred Health, Carlton, VIC, Australia; Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Jane S Hocking
- Melbourne Sexual Health Centre, Alfred Health, Carlton, VIC, Australia; University of Melbourne, Parkville, VIC, Australia
| | - Eric P F Chow
- Melbourne Sexual Health Centre, Alfred Health, Carlton, VIC, Australia; Central Clinical School, Monash University, Melbourne, VIC, Australia
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16
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Whittles LK, White PJ, Didelot X. A dynamic power-law sexual network model of gonorrhoea outbreaks. PLoS Comput Biol 2019; 15:e1006748. [PMID: 30849080 PMCID: PMC6426262 DOI: 10.1371/journal.pcbi.1006748] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 03/20/2019] [Accepted: 01/04/2019] [Indexed: 11/26/2022] Open
Abstract
Human networks of sexual contacts are dynamic by nature, with partnerships forming and breaking continuously over time. Sexual behaviours are also highly heterogeneous, so that the number of partners reported by individuals over a given period of time is typically distributed as a power-law. Both the dynamism and heterogeneity of sexual partnerships are likely to have an effect in the patterns of spread of sexually transmitted diseases. To represent these two fundamental properties of sexual networks, we developed a stochastic process of dynamic partnership formation and dissolution, which results in power-law numbers of partners over time. Model parameters can be set to produce realistic conditions in terms of the exponent of the power-law distribution, of the number of individuals without relationships and of the average duration of relationships. Using an outbreak of antibiotic resistant gonorrhoea amongst men have sex with men as a case study, we show that our realistic dynamic network exhibits different properties compared to the frequently used static networks or homogeneous mixing models. We also consider an approximation to our dynamic network model in terms of a much simpler branching process. We estimate the parameters of the generation time distribution and offspring distribution which can be used for example in the context of outbreak reconstruction based on genomic data. Finally, we investigate the impact of a range of interventions against gonorrhoea, including increased condom use, more frequent screening and immunisation, concluding that the latter shows great promise to reduce the burden of gonorrhoea, even if the vaccine was only partially effective or applied to only a random subset of the population.
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Affiliation(s)
- Lilith K. Whittles
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Peter J. White
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
- Modelling and Economics Unit, National Infection Service, Public Health England, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
- NIHR Health Protection Research Unit in Modelling Methodology, School of Public Health, Imperial College London, London, United Kingdom
| | - Xavier Didelot
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Department of Statistics, University of Warwick, Coventry, United Kingdom
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17
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Modelling the Epidemiological Impact and Cost-Effectiveness of PrEP for HIV Transmission in MSM in China. AIDS Behav 2019; 23:523-533. [PMID: 29971734 DOI: 10.1007/s10461-018-2205-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Risk of HIV infection is high in Chinese MSM, with an annual HIV incidence ranging from 3.41 to 13.7/100 person-years. Tenofovir-based PrEP is effective in preventing HIV transmission in MSM. This study evaluates the epidemiological impact and cost-effectiveness of implementing PrEP in Chinese MSM over the next two decades. A compartmental model for HIV was used to forecast the impact of PrEP on number of infections, deaths, and disability-adjusted life years (DALY) averted. We also provide an estimate of the incremental cost-effectiveness ratio (ICER) and the cost per DALY averted of the intervention. Without PrEP, there will be 1.1-3.0 million new infections and 0.7-2.3 million HIV-related deaths in the next two decades. Moderate PrEP coverage (50%) would prevent 0.17-0.32 million new HIV infections. At Truvada's current price in China, daily oral PrEP costs $46,813-52,008 per DALY averted and is not cost-effective; on-demand Truvada reduces ICER to $25,057-27,838 per DALY averted, marginally cost-effective; daily generic tenofovir-based regimens further reduce ICER to $3675-8963, wholly cost-effective. The cost of daily oral Truvada PrEP regimen would need to be reduced by half to achieve cost-effectiveness and realize the public health good of preventing hundreds of thousands of HIV infections among MSM in China.
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18
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Kenyon CR, Delva W. It's the network, stupid: a population's sexual network connectivity determines its STI prevalence. F1000Res 2018; 7:1880. [PMID: 30815252 PMCID: PMC6376253 DOI: 10.12688/f1000research.17148.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/21/2018] [Indexed: 10/06/2023] Open
Abstract
There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.
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Affiliation(s)
- Chris R. Kenyon
- Institute of Tropical Medicine, Antwerp, Antwerp, 2000, Belgium
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Wim Delva
- Department of Global Health, University of Stellenbosch, Stellenbosch, South Africa
- International Centre for Reproductive Health, Ghent University, Ghent, Belgium
- South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
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19
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Kenyon CR, Delva W. It's the network, stupid: a population's sexual network connectivity determines its STI prevalence. F1000Res 2018; 7:1880. [PMID: 30815252 PMCID: PMC6376253 DOI: 10.12688/f1000research.17148.2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/23/2019] [Indexed: 11/20/2022] Open
Abstract
There is little consensus as to why sexually transmitted infections (STIs), including HIV and bacterial vaginosis (BV) are more prevalent in some populations than others. Using a broad definition of sexual network connectivity that includes both structural and conductivity-related factors, we argue that the available evidence suggests that high prevalence of traditional STIs, HIV and BV can be parsimoniously explained by these populations having more connected sexual networks. Positive feedback, whereby BV and various STIs enhance the spread of other STIs, then further accentuates the spread of BV, HIV and other STIs. We review evidence that support this hypothesis and end by suggesting study designs that could further evaluate the hypothesis, as well as implications of this hypothesis for the prevention and management of STIs.
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Affiliation(s)
- Chris R. Kenyon
- Institute of Tropical Medicine, Antwerp, Antwerp, 2000, Belgium
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Wim Delva
- Department of Global Health, University of Stellenbosch, Stellenbosch, South Africa
- International Centre for Reproductive Health, Ghent University, Ghent, Belgium
- South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
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20
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Fairley CK, Hocking JS, Zhang L, Chow EPF. Frequent Transmission of Gonorrhea in Men Who Have Sex with Men. Emerg Infect Dis 2018; 23:102-104. [PMID: 27983487 PMCID: PMC5176237 DOI: 10.3201/eid2301.161205] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The rate of gonorrhea is much higher in men who have sex with men than in heterosexuals. Because of unique behavioral characteristics, asymptomatic sites of infection, mainly the pharynx, are principal drivers of gonorrhea prevalence in men who have sex with men. On the basis of this observation, we call for interventions.
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21
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Current levels of gonorrhoea screening in MSM in Belgium may have little effect on prevalence: a modelling study. Epidemiol Infect 2018; 146:333-338. [PMID: 29386078 DOI: 10.1017/s0950268818000092] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
There is considerable uncertainty as to the effectiveness of Neisseria gonorrhoeae (NG) screening in men who have sex with men. It is important to ensure that screening has benefits that outweigh the risks of increased antibiotics resistance. We develop a mathematical model to estimate the effectiveness of screening on prevalence. Separable Temporal Exponential family Random Graph Models are used to model the sexual relationships network, both with main and casual partners. Next, the transmission of Gonorrhoea is simulated on this network. The models are implemented using the R package 'statnet', which we adapted among other things to incorporate infection status at the pharynx, urethra and rectum separately and to distinguish between anal sex, oral sex and rimming. The different screening programmes compared are no screening, 3.5% of the population screened, 32% screened and 50% screened. The model simulates day-by-day evolution for 10 years of a population of 10 000. If half of the population would be screened, the prevalence in the pharynx decreases from 11.9% to 10.2%. We conclude that the limited impact of screening on NG prevalence may not outweigh the increased risk of antibiotic resistance.
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22
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Tuite AR, Gift TL, Chesson HW, Hsu K, Salomon JA, Grad YH. Impact of Rapid Susceptibility Testing and Antibiotic Selection Strategy on the Emergence and Spread of Antibiotic Resistance in Gonorrhea. J Infect Dis 2017; 216:1141-1149. [PMID: 28968710 PMCID: PMC5853443 DOI: 10.1093/infdis/jix450] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 08/29/2017] [Indexed: 12/22/2022] Open
Abstract
Background Increasing antibiotic resistance limits treatment options for gonorrhea. We examined the impact of a hypothetical point-of-care (POC) test reporting antibiotic susceptibility profiles on slowing resistance spread. Methods A mathematical model describing gonorrhea transmission incorporated resistance emergence probabilities and fitness costs associated with resistance based on characteristics of ciprofloxacin (A), azithromycin (B), and ceftriaxone (C). We evaluated time to 1% and 5% prevalence of resistant strains among all isolates with the following: (1) empiric treatment (B and C), and treatment guided by POC tests determining susceptibility to (2) A only and (3) all 3 antibiotics. Results Continued empiric treatment without POC testing was projected to result in >5% of isolates being resistant to both B and C within 15 years. Use of either POC test in 10% of identified cases delayed this by 5 years. The 3 antibiotic POC test delayed the time to reach 1% prevalence of triply-resistant strains by 6 years, whereas the A-only test resulted in no delay. Results were less sensitive to assumptions about fitness costs and test characteristics with increasing test uptake. Conclusions Rapid diagnostics reporting antibiotic susceptibility may extend the usefulness of existing antibiotics for gonorrhea treatment, but ongoing monitoring of resistance patterns will be critical.
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Affiliation(s)
- Ashleigh R Tuite
- Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Thomas L Gift
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | | | - Joshua A Salomon
- Harvard T. H. Chan School of Public Health, Boston, Massachusetts
| | - Yonatan H Grad
- Harvard T. H. Chan School of Public Health, Boston, Massachusetts
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Birger R, Saunders J, Estcourt C, Sutton AJ, Mercer CH, Roberts T, White PJ. Should we screen for the sexually-transmitted infection Mycoplasma genitalium? Evidence synthesis using a transmission-dynamic model. Sci Rep 2017; 7:16162. [PMID: 29170443 PMCID: PMC5700964 DOI: 10.1038/s41598-017-16302-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/09/2017] [Indexed: 11/17/2022] Open
Abstract
There is increasing concern about Mycoplasma genitalium as a cause of urethritis, cervicitis, pelvic inflammatory disease (PID), infertility and ectopic pregnancy. Commercial nucleic acid amplification tests (NAATs) are becoming available, and their use in screening for M. genitalium has been advocated, but M. genitalium's natural history is poorly-understood, making screening's effectiveness unclear. We used a transmission-dynamic compartmental model to synthesise evidence from surveillance data and epidemiological and behavioural studies to better understand M. genitalium's natural history, and then examined the effects of implementing NAAT testing. Introducing NAAT testing initially increases diagnoses, by finding a larger proportion of infections; subsequently the diagnosis rate falls, due to reduced incidence. Testing only symptomatic patients finds relatively little infection in women, as a large proportion is asymptomatic. Testing both symptomatic and asymptomatic patients has a much larger impact and reduces cumulative PID incidence in women due to M. genitalium by 31.1% (95% range:13.0%-52.0%) over 20 years. However, there is important uncertainty in M. genitalium's natural history parameters, leading to uncertainty in the absolute reduction in PID and sequelae. Empirical work is required to improve understanding of key aspects of M. genitalium's natural history before it will be possible to determine the effectiveness of screening.
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Affiliation(s)
- Ruthie Birger
- MRC Centre for Outbreak Analysis & Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG, UK.
- Earth Institute & Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 W 168th Street, New York, NY, USA.
| | - John Saunders
- Centre for Immunology & Infectious Disease, Blizard Institute, Barts and The London School of Medicine & Dentistry, The Blizard Building, 4 Newark Street, London, E1 2AT, UK
- Barts Health NHS Trust, Turner St, Whitechapel, London, E1 1BB, UK
| | - Claudia Estcourt
- Centre for Immunology & Infectious Disease, Blizard Institute, Barts and The London School of Medicine & Dentistry, The Blizard Building, 4 Newark Street, London, E1 2AT, UK
- Barts Health NHS Trust, Turner St, Whitechapel, London, E1 1BB, UK
- School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, Scotland, UK
| | - Andrew John Sutton
- Health Economics Unit, Leeds Institute of Health Sciences, University of Leeds, Level 11, Worsley Building, Clarendon Way, Leeds, LS2 9JT, UK
- NIHR Diagnostic Evidence Co-operative, Clinical Sciences Building, St James's University Hospital, Leeds, LS9 7TF, UK
| | - Catherine H Mercer
- Institute for Global Health, University College London, 3rd floor Mortimer Market Centre off Capper Street, London, WC1E 6JB, UK
| | - Tracy Roberts
- Health Economics Unit, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Peter J White
- MRC Centre for Outbreak Analysis & Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG, UK.
- NIHR Health Protection Research Unit in Modelling Methodology, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG, UK.
- Modelling & Economics Unit, National Infection Service, Public Health England, 61 Colindale Avenue, London, NW9 5EQ, UK.
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24
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Should we screen for the sexually-transmitted infection Mycoplasma genitalium? Evidence synthesis using a transmission-dynamic model. Sci Rep 2017. [PMID: 29170443 DOI: 10.1038/s41598-01716302-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
There is increasing concern about Mycoplasma genitalium as a cause of urethritis, cervicitis, pelvic inflammatory disease (PID), infertility and ectopic pregnancy. Commercial nucleic acid amplification tests (NAATs) are becoming available, and their use in screening for M. genitalium has been advocated, but M. genitalium's natural history is poorly-understood, making screening's effectiveness unclear. We used a transmission-dynamic compartmental model to synthesise evidence from surveillance data and epidemiological and behavioural studies to better understand M. genitalium's natural history, and then examined the effects of implementing NAAT testing. Introducing NAAT testing initially increases diagnoses, by finding a larger proportion of infections; subsequently the diagnosis rate falls, due to reduced incidence. Testing only symptomatic patients finds relatively little infection in women, as a large proportion is asymptomatic. Testing both symptomatic and asymptomatic patients has a much larger impact and reduces cumulative PID incidence in women due to M. genitalium by 31.1% (95% range:13.0%-52.0%) over 20 years. However, there is important uncertainty in M. genitalium's natural history parameters, leading to uncertainty in the absolute reduction in PID and sequelae. Empirical work is required to improve understanding of key aspects of M. genitalium's natural history before it will be possible to determine the effectiveness of screening.
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25
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Whitlock GG, Gibbons DC, Longford N, Harvey MJ, McOwan A, Adams EJ. Rapid testing and treatment for sexually transmitted infections improve patient care and yield public health benefits. Int J STD AIDS 2017; 29:474-482. [PMID: 29059032 PMCID: PMC5844454 DOI: 10.1177/0956462417736431] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A service evaluation of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) testing and result notification in patients attending a rapid testing service (Dean Street Express [DSE]) compared with those attending an existing 'standard' sexual health clinic (56 Dean Street [56DS]), and modelling the impact of the new service from 1 June 2014 to 31 May 2015. PRIMARY OUTCOME time from patients' sample collection to notification of test results at DSE compared with 56DS. Secondary outcomes estimated using a model: number of transmissions prevented and the number of new partner visits avoided and associated cost savings achieved due to rapid testing at DSE. In 2014/15, there were a total of 81,352 visits for CT/NG testing across 56DS (21,086) and DSE (60,266). Rapid testing resulted in a reduced mean time to notification of 8.68 days: 8.95 days for 56DS (95% CI 8.91-8.99) compared to 0.27 days for DSE (95% CI 0.26-0.28). Our model estimates that rapid testing at DSE would lead to 196 CT and/or NG transmissions prevented (2.5-97.5% centile range = 6-956) and lead to annual savings attributable to reduced numbers of partner attendances of £124,283 (2.5-97.5% centile range = £4260-590,331). DSE, a rapid testing service for asymptomatic infections, delivers faster time to result notification for CT and/or NG which enables faster treatment, reduces infectious periods and leads to fewer transmissions, partner attendances and clinic costs.
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Affiliation(s)
- Gary G Whitlock
- 1 GUM/HIV, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Daniel C Gibbons
- 2 Aquarius Population Health Limited, London, UK.,3 Department of Primary Care and Public Health, School of Public Health, Imperial College London, London, UK
| | - Nick Longford
- 4 Division of Medicine, Imperial College London, London, UK
| | | | - Alan McOwan
- 1 GUM/HIV, Chelsea and Westminster NHS Foundation Trust, London, UK
| | - Elisabeth J Adams
- 2 Aquarius Population Health Limited, London, UK.,5 School of Social and Community Medicine, University of Bristol, Bristol, UK
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Whittles LK, White PJ, Didelot X. Estimating the fitness cost and benefit of cefixime resistance in Neisseria gonorrhoeae to inform prescription policy: A modelling study. PLoS Med 2017; 14:e1002416. [PMID: 29088226 PMCID: PMC5663337 DOI: 10.1371/journal.pmed.1002416] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/26/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Gonorrhoea is one of the most common bacterial sexually transmitted infections in England. Over 41,000 cases were recorded in 2015, more than half of which occurred in men who have sex with men (MSM). As the bacterium has developed resistance to each first-line antibiotic in turn, we need an improved understanding of fitness benefits and costs of antibiotic resistance to inform control policy and planning. Cefixime was recommended as a single-dose treatment for gonorrhoea from 2005 to 2010, during which time resistance increased, and subsequently declined. METHODS AND FINDINGS We developed a stochastic compartmental model representing the natural history and transmission of cefixime-sensitive and cefixime-resistant strains of Neisseria gonorrhoeae in MSM in England, which was applied to data on diagnoses and prescriptions between 2008 and 2015. We estimated that asymptomatic carriers play a crucial role in overall transmission dynamics, with 37% (95% credible interval CrI 24%-52%) of infections remaining asymptomatic and untreated, accounting for 89% (95% CrI 82%-93%) of onward transmission. The fitness cost of cefixime resistance in the absence of cefixime usage was estimated to be such that the number of secondary infections caused by resistant strains is only about half as much as for the susceptible strains, which is insufficient to maintain persistence. However, we estimated that treatment of cefixime-resistant strains with cefixime was unsuccessful in 83% (95% CrI 53%-99%) of cases, representing a fitness benefit of resistance. This benefit was large enough to counterbalance the fitness cost when 31% (95% CrI 26%-36%) of cases were treated with cefixime, and when more than 55% (95% CrI 44%-66%) of cases were treated with cefixime, the resistant strain had a net fitness advantage over the susceptible strain. Limitations include sparse data leading to large intervals on key model parameters and necessary assumptions in the modelling of a complex epidemiological process. CONCLUSIONS Our study provides, to our knowledge, the first estimates of the fitness cost and benefit associated with resistance of the gonococcus to a clinically relevant antibiotic. Our findings have important implications for antibiotic stewardship and public health policies and, in particular, suggest that a previously abandoned antibiotic could be used again to treat a minority of gonorrhoea cases without raising resistance levels.
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Affiliation(s)
- Lilith K Whittles
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Peter J White
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom.,MRC Centre for Outbreak Analysis and Modelling, School of Public Health, Imperial College London, London, United Kingdom.,NIHR Health Protection Research Unit in Modelling Methodology, School of Public Health, Imperial College London, London, United Kingdom.,Modelling and Economics Unit, National Infection Service, Public Health England, London, United Kingdom
| | - Xavier Didelot
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
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Adaptation of the HIV Care Continuum as a Method for Evaluating Syphilis and Gonorrhea Disease Control Activities in Los Angeles County. Sex Transm Dis 2016; 42:686-90. [PMID: 26562697 DOI: 10.1097/olq.0000000000000366] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Treatment verification and contact elicitation are core approaches used to control the spread of sexually transmitted diseases (STDs). Methodology adapted from the HIV care continuum is presented as an evaluation and communication tool for STD control activities. METHODS Sexually transmitted disease surveillance and program data for Los Angeles County in 2013 were used to construct a 2-part continuum to examine syphilis (all stages) and gonorrhea outcomes among index patients and elicited contacts. The Index Case Continuum (Part 1) assesses the proportion of patients who were treated, assigned for interview, interviewed, and provided name and locating information for at least 1 contact. The Elicited Contact Continuum (Part 2) assesses the proportion of contacts who were located, interviewed, and treated. RESULTS Among 3668 patients with syphilis, 97% (n = 3556) were treated, 72% (n = 2633) were interviewed, and 25% (n = 920) provided name and locating information for at least 1 contact. The corresponding numbers for 12,541 gonorrhea cases were 95% (n = 11,936), 45% (n = 5633), and 16% (1944), respectively. Among the 1392 contacts elicited from syphilis cases, 53% (n = 735) were either interviewed or determined to not need an interview and 43% (n = 595) were treated. The corresponding numbers for the 2323 contacts elicited from gonorrhea cases were 53% (n = 1221) and 46% (n = 1075), respectively. CONCLUSIONS Adaptation of the HIV continuum is a useful tool for evaluating treatment verification and contact elicitation activities. In Los Angeles County, this approach revealed significant drop-offs in the proportion of index cases naming contacts and in the proportion of contacts who are interviewed and treated.
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Whole-genome sequencing to determine transmission of Neisseria gonorrhoeae: an observational study. THE LANCET. INFECTIOUS DISEASES 2016; 16:1295-1303. [PMID: 27427203 DOI: 10.1016/s1473-3099(16)30157-8] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/13/2016] [Accepted: 05/31/2016] [Indexed: 11/23/2022]
Abstract
BACKGROUND New approaches are urgently required to address increasing rates of gonorrhoea and the emergence and global spread of antibiotic-resistant Neisseria gonorrhoeae. We used whole-genome sequencing to study transmission and track resistance in N gonorrhoeae isolates. METHODS We did whole-genome sequencing of isolates obtained from samples collected from patients attending sexual health services in Brighton, UK, between Jan 1, 2011, and March 9, 2015. We also included isolates from other UK locations, historical isolates from Brighton, and previous data from a US study. Samples from symptomatic patients and asymptomatic sexual health screening underwent nucleic acid amplification testing; positive samples and all samples from symptomatic patients were cultured for N gonorrhoeae, and resulting isolates were whole-genome sequenced. Cefixime susceptibility testing was done in selected isolates by agar incorporation, and we used sequence data to determine multi-antigen sequence types and penA genotypes. We derived a transmission nomogram to determine the plausibility of direct or indirect transmission between any two cases depending on the time between samples: estimated mutation rates, plus diversity noted within patients across anatomical sites and probable transmission pairs, were used to fit a coalescent model to determine the number of single nucleotide polymorphisms expected. FINDINGS 1407 (98%) of 1437 Brighton isolates between Jan 1, 2011, and March 9, 2015 were successfully sequenced. We identified 1061 infections from 907 patients. 281 (26%) of these infections were indistinguishable (ie, differed by zero single nucleotide polymorphisms) from one or more previous cases, and 786 (74%) had evidence of a sampled direct or indirect Brighton source. We observed multiple related samples across geographical locations. Of 1273 infections in Brighton (including historical data), 225 (18%) were linked to another case elsewhere in the UK, and 115 (9%) to a case in the USA. Four lineages initially identified in Brighton could be linked to 70 USA sequences, including 61 from a lineage carrying the mosaic penA XXXIV allele, which is associated with reduced cefixime susceptibility. INTERPRETATION We present a whole-genome-sequencing-based tool for genomic contact tracing of N gonorrhoeae and demonstrate local, national, and international transmission. Whole-genome sequencing can be applied across geographical boundaries to investigate gonorrhoea transmission and to track antimicrobial resistance. FUNDING Oxford National Institute for Health Research Health Protection Research Unit and Biomedical Research Centre.
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Abstract
Gonorrhea is a sexually transmitted disease causing growing concern, with a substantial increase in reported incidence over the past few years in the United Kingdom and rising levels of resistance to a wide range of antibiotics. Understanding its epidemiology is therefore of major biomedical importance, not only on a population scale but also at the level of direct transmission. However, the molecular typing techniques traditionally used for gonorrhea infections do not provide sufficient resolution to investigate such fine-scale patterns. Here we sequenced the genomes of 237 isolates from two local collections of isolates from Sheffield and London, each of which was resolved into a single type using traditional methods. The two data sets were selected to have different epidemiological properties: the Sheffield data were collected over 6 years from a predominantly heterosexual population, whereas the London data were gathered within half a year and strongly associated with men who have sex with men. Based on contact tracing information between individuals in Sheffield, we found that transmission is associated with a median time to most recent common ancestor of 3.4 months, with an upper bound of 8 months, which we used as a criterion to identify likely transmission links in both data sets. In London, we found that transmission happened predominantly between individuals of similar age, sexual orientation, and location and also with the same HIV serostatus, which may reflect serosorting and associated risk behaviors. Comparison of the two data sets suggests that the London epidemic involved about ten times more cases than the Sheffield outbreak. The recent increases in gonorrhea incidence and antibiotic resistance are cause for public health concern. Successful intervention requires a better understanding of transmission patterns, which is not uncovered by traditional molecular epidemiology techniques. Here we studied two outbreaks that took place in Sheffield and London, United Kingdom. We show that whole-genome sequencing provides the resolution to investigate direct gonorrhea transmission between infected individuals. Combining genome sequencing with rich epidemiological information about infected individuals reveals the importance of several transmission routes and risk factors, which can be used to design better control measures.
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Fingerhuth SM, Bonhoeffer S, Low N, Althaus CL. Antibiotic-Resistant Neisseria gonorrhoeae Spread Faster with More Treatment, Not More Sexual Partners. PLoS Pathog 2016; 12:e1005611. [PMID: 27196299 PMCID: PMC4872991 DOI: 10.1371/journal.ppat.1005611] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 04/12/2016] [Indexed: 11/18/2022] Open
Abstract
The sexually transmitted bacterium Neisseria gonorrhoeae has developed resistance to all antibiotic classes that have been used for treatment and strains resistant to multiple antibiotic classes have evolved. In many countries, there is only one antibiotic remaining for empirical N. gonorrhoeae treatment, and antibiotic management to counteract resistance spread is urgently needed. Understanding dynamics and drivers of resistance spread can provide an improved rationale for antibiotic management. In our study, we first used antibiotic resistance surveillance data to estimate the rates at which antibiotic-resistant N. gonorrhoeae spread in two host populations, heterosexual men (HetM) and men who have sex with men (MSM). We found higher rates of spread for MSM (0.86 to 2.38 y−1, mean doubling time: 6 months) compared to HetM (0.24 to 0.86 y−1, mean doubling time: 16 months). We then developed a dynamic transmission model to reproduce the observed dynamics of N. gonorrhoeae transmission in populations of heterosexual men and women (HMW) and MSM. We parameterized the model using sexual behavior data and calibrated it to N. gonorrhoeae prevalence and incidence data. In the model, antibiotic-resistant N. gonorrhoeae spread with a median rate of 0.88 y−1 in HMW and 3.12 y−1 in MSM. These rates correspond to median doubling times of 9 (HMW) and 3 (MSM) months. Assuming no fitness costs, the model shows the difference in the host population’s treatment rate rather than the difference in the number of sexual partners explains the differential spread of resistance. As higher treatment rates result in faster spread of antibiotic resistance, treatment recommendations for N. gonorrhoeae should carefully balance prevention of infection and avoidance of resistance spread. More and more infectious disease treatments fail because the causative pathogens are resistant to the drugs used for treatment. For the treatment of Neisseria gonorrhoeae, a sexually transmitted bacterium, drug resistance is a particularly big problem: there is only a single antibiotic left that is recommended for treatment. We aimed to understand how antibiotic-resistant N. gonorrhoeae spread in a sexually active host population and how the spread of resistance can be slowed. From antibiotic resistance surveillance data, we first estimated the rate at which antibiotic-resistant N. gonorrhoeae spread. Second, we reproduced the observed dynamics in a mathematical model describing the transmission between hosts. We found that antibiotic-resistant N. gonorrhoeae spread faster in host populations of men who have sex with men than in host populations of heterosexuals. We could attribute the faster spread of resistant pathogens to higher treatment rates. This finding implies that promoting screening to control antibiotic-resistant N. gonorrhoeae could in fact accelerate their spread.
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Affiliation(s)
- Stephanie M. Fingerhuth
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
- * E-mail:
| | | | - Nicola Low
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Christian L. Althaus
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
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Hui BB, Wilson DP, Ward JS, Guy RJ, Kaldor JM, Law MG, Hocking JS, Regan DG. The potential impact of new generation molecular point-of-care tests on gonorrhoea and chlamydia in a setting of high endemic prevalence. Sex Health 2016; 10:348-56. [PMID: 23806149 DOI: 10.1071/sh13026] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/04/2013] [Indexed: 11/23/2022]
Abstract
UNLABELLED Background Despite the availability of testing and treatment, bacterial sexually transmissible infections (STIs) continue to occur at endemic levels in many remote Indigenous communities in Australia. New generation molecular point-of-care (POC) tests have high sensitivity, comparable with conventional diagnostic tests, and have the potential to increase the impact of STI screening. METHODS We developed mathematical models of gonorrhoea (Neisseria gonorrhoeae) and chlamydia (Chlamydia trachomatis) transmission in remote Indigenous communities in Australia to evaluate screening and treatment strategies that utilise POC tests. RESULTS The introduction of POC testing with 95% sensitivity could reduce the prevalence of gonorrhoea and chlamydia from 7.1% and 11.9% to 5.7% and 8.9%, respectively, under baseline screening coverage of 44% per year. If screening coverage is increased to 60% per year, prevalence is predicted to be reduced to 3.6% and 6.7%, respectively, under conventional testing, and further reduced to 1.8% and 3.1% with the introduction of POC testing. Increasing screening coverage to 80% per year will result in a reduction in the prevalence of gonorrhoea and chlamydia to 0.6% and 1.5%, respectively, and the virtual elimination of both STIs if POC testing is introduced. CONCLUSIONS Modelling suggests that molecular POC tests of high sensitivity have great promise as a public health strategy for controlling chlamydia and gonorrhoea. However, evaluation of the cost-effectiveness of POC testing needs to be made before widespread implementation of this technology can be considered.
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Affiliation(s)
- Ben B Hui
- The Kirby Institute, University of New South Wales, Sydney, NSW 2052, Australia
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Chow EPF, Cornelisse VJ, Read TRH, Lee D, Walker S, Hocking JS, Chen MY, Bradshaw CS, Fairley CK. Saliva use as a lubricant for anal sex is a risk factor for rectal gonorrhoea among men who have sex with men, a new public health message: a cross-sectional survey. Sex Transm Infect 2016; 92:532-536. [PMID: 26941362 DOI: 10.1136/sextrans-2015-052502] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 02/02/2016] [Accepted: 02/14/2016] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Apart from penile-anal intercourse, other anal sexual practices (rimming, fingering and saliva use as a lubricant for anal sex) are common among men who have sex with men (MSM). The aim of this study is to evaluate whether these anal sexual practices are risk factors for rectal gonorrhoea in MSM. METHOD A cross-sectional survey was conducted among MSM attending Melbourne Sexual Health Centre between 31 July 2014 and 30 June 2015. Rectal gonorrhoea cases were identified by culture. RESULTS Among 1312 MSM, 4.3% (n=56) had rectal gonorrhoea. Other anal sexual practices were common among MSM: receptive rimming (70.5%), receptive fingering or penis dipping (84.3%) and using partner's saliva as a lubricant for anal sex (68.5%). Saliva as a lubricant (adjusted OR 2.17; 95% CI 1.00 to 4.71) was significantly associated with rectal gonorrhoea after adjusting for potential confounding factors. Receptive rimming and fingering or penis dipping were not statistically associated with rectal gonorrhoea. The crude population-attributable fraction of rectal gonorrhoea associated with use of partner's saliva as a lubricant for anal sex was 48.9% (7.9% to 71.7%). CONCLUSIONS Saliva use as a lubricant for anal sex is a common sexual practice in MSM, and it may play an important role in gonorrhoea transmission. Almost half of rectal gonorrhoea cases may be eliminated if MSM stopped using partner's saliva for anal sex.
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Affiliation(s)
- Eric P F Chow
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Vincent J Cornelisse
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Tim R H Read
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - David Lee
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia
| | - Sandra Walker
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Jane S Hocking
- Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Marcus Y Chen
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Catriona S Bradshaw
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Christopher K Fairley
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia.,Faculty of Medicine, Central Clinical School, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
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Hazel A, Marino S, Simon C. An anthropologically based model of the impact of asymptomatic cases on the spread of Neisseria gonorrhoeae. J R Soc Interface 2016; 12:rsif.2015.0067. [PMID: 25808340 DOI: 10.1098/rsif.2015.0067] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neisseria gonorrhoeae (GC) remains a serious burden in many high-sexual-activity, undertreated populations. Using empirical data from a 2009 study of GC burden among pastoralists in Kaokoveld, Namibia, we expand the standard gonorrhoea transmission model by using locally derived sexual contact data to explore transmission dynamics in a population with high rates of partner exchange and low treatment-seeking behaviour. We use the model to generate ball-park estimates for transmission probabilities and other parameter values for low-level (i.e. less than approx. 1200 copies/20 µl PCR reaction) asymptomatic infections, which account for 74% of all GC infections found in Kaokoveld in 2009, and to describe the impact of asymptomatic, low-level infections on overall prevalence patterns. Our results suggest that GC transmission probabilities are higher than previously estimated, that untreated infections take longer to clear than previously estimated and that a high prevalence of low-level infections is partially due to larger numbers of untreated, asymptomatic infections. These results provide new insights into the natural history of GC and the challenge of syndromic management programmes for the eradication of endemic gonorrhoea.
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Affiliation(s)
- Ashley Hazel
- School of Natural Resources and Environment, University of Michigan, Dana Building, 440 Church Street, Ann Arbor, MI 48109, USA Department of Anthropology, Stanford University, 450 Serra Mall, Building 50, Stanford, CA 94305, USA
| | - Simeone Marino
- School of Medicine, Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109-0620, USA
| | - Carl Simon
- Department of Mathematics, Ford School of Public Policy, Center for the Study of Complex Systems, University of Michigan, Weill Hall, 735 South State Street no. 4203, Ann Arbor, MI 48109, USA
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Owusu-Edusei K, Chesson HW, Gift TL, Brunham RC, Bolan G. Cost-effectiveness of Chlamydia vaccination programs for young women. Emerg Infect Dis 2015; 21:960-8. [PMID: 25989525 PMCID: PMC4451885 DOI: 10.3201/eid2106.141270] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A successful vaccine could be a cost-effective addition to current screening practices. We explored potential cost-effectiveness of a chlamydia vaccine for young women in the United States by using a compartmental heterosexual transmission model. We tracked health outcomes (acute infections and sequelae measured in quality-adjusted life-years [QALYs]) and determined incremental cost-effectiveness ratios (ICERs) over a 50-year analytic horizon. We assessed vaccination of 14-year-old girls and catch-up vaccination for 15–24-year-old women in the context of an existing chlamydia screening program and assumed 2 prevaccination prevalences of 3.2% by main analysis and 3.7% by additional analysis. Estimated ICERs of vaccinating 14-year-old girls were $35,300/QALY by main analysis and $16,200/QALY by additional analysis compared with only screening. Catch-up vaccination for 15–24-year-old women resulted in estimated ICERs of $53,200/QALY by main analysis and $26,300/QALY by additional analysis. The ICER was most sensitive to prevaccination prevalence for women, followed by cost of vaccination, duration of vaccine-conferred immunity, and vaccine efficacy. Our results suggest that a successful chlamydia vaccine could be cost-effective.
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Grad YH, Goldstein E, Lipsitch M, White PJ. Improving Control of Antibiotic-Resistant Gonorrhea by Integrating Research Agendas Across Disciplines: Key Questions Arising From Mathematical Modeling. J Infect Dis 2015; 213:883-90. [PMID: 26518045 DOI: 10.1093/infdis/jiv517] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/19/2015] [Indexed: 11/15/2022] Open
Abstract
The rise in gonococcal antibiotic resistance and the threat of untreatable infection are focusing attention on strategies to limit the spread of drug-resistant gonorrhea. Mathematical models provide a framework to link the natural history of infection and patient behavior to epidemiological outcomes and can be used to guide research and enhance the public health impact of interventions. While limited knowledge of key disease parameters and networks of spread has impeded development of operational models of gonococcal transmission, new tools in gonococcal surveillance may provide useful data to aid tracking and modeling. Here, we highlight critical questions in the management of gonorrhea that can be addressed by mathematical models and identify key data needs. Our overarching aim is to articulate a shared agenda across gonococcus-related fields from microbiology to epidemiology that will catalyze a comprehensive evidence-based clinical and public health strategy for management of gonococcal infections and antimicrobial resistance.
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Affiliation(s)
- Yonatan H Grad
- Department of Immunology and Infectious Diseases Department of Epidemiology, Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, and Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Edward Goldstein
- Department of Epidemiology, Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, and
| | - Marc Lipsitch
- Department of Immunology and Infectious Diseases Department of Epidemiology, Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, and
| | - Peter J White
- Modelling and Economics Unit, Centre for Infectious Disease Surveillance and Control, Public Health England MRC Centre for Outbreak Analysis and Modelling NIHR Health Protection Research Unit in Modelling Methodology, School of Public Health, Imperial College London, United Kingdom
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Exploring the Benefits of Molecular Testing for Gonorrhoea Antibiotic Resistance Surveillance in Remote Settings. PLoS One 2015; 10:e0133202. [PMID: 26181042 PMCID: PMC4504484 DOI: 10.1371/journal.pone.0133202] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 06/24/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Surveillance for gonorrhoea antimicrobial resistance (AMR) is compromised by a move away from culture-based testing in favour of more convenient nucleic acid amplification test (NAAT) tests. We assessed the potential benefit of a molecular resistance test in terms of the timeliness of detection of gonorrhoea AMR. METHODS AND FINDINGS An individual-based mathematical model was developed to describe the transmission of gonorrhoea in a remote Indigenous population in Australia. We estimated the impact of the molecular test on the time delay between first importation and the first confirmation that the prevalence of gonorrhoea AMR (resistance proportion) has breached the WHO-recommended 5% threshold (when a change in antibiotic should occur). In the remote setting evaluated in this study, the model predicts that when culture is the only available means of testing for AMR, the breach will only be detected when the actual prevalence of AMR in the population has already reached 8 - 18%, with an associated delay of ~43 - 69 months between first importation and detection. With the addition of a molecular resistance test, the number of samples for which AMR can be determined increases facilitating earlier detection at a lower resistance proportion. For the best case scenario, where AMR can be determined for all diagnostic samples, the alert would be triggered at least 8 months earlier than using culture alone and the resistance proportion will have only slightly exceeded the 5% notification threshold. CONCLUSIONS Molecular tests have the potential to provide more timely warning of the emergence of gonorrhoea AMR. This in turn will facilitate earlier treatment switching and more targeted treatment, which has the potential to reduce the population impact of gonorrhoea AMR.
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Hui B, Fairley CK, Chen M, Grulich A, Hocking J, Prestage G, Walker S, Law M, Regan D. Oral and anal sex are key to sustaining gonorrhoea at endemic levels in MSM populations: a mathematical model. Sex Transm Infect 2015; 91:365-9. [PMID: 25596192 DOI: 10.1136/sextrans-2014-051760] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 12/14/2014] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES Despite early treatment of urethral infection, gonorrhoea is endemic in urban populations of men who have sex with men (MSM) in Australia. By contrast, gonorrhoea is not common in urban heterosexual populations. Sexual activities among MSM usually involve anal or oral sex, and as these behaviours are becoming increasingly common among heterosexuals, there is a need to investigate their roles in transmission of gonorrhoea. METHODS We developed individual-based models of transmission of gonorrhoea in MSM and heterosexuals that incorporate anatomical site-specific transmission of gonorrhoea. We estimated the probabilities of transmission for anal sex and oral sex by calibrating an MSM model against prevalence of gonorrhoea and sexual activity data. These probabilities were then applied to a heterosexual model in order to examine whether gonorrhoea can persist in a heterosexual population through the addition of anal sex and oral sex. RESULTS In the MSM model, gonorrhoea can persist despite prompt treatment of urethral infections. The probability of gonorrhoea persisting is reduced if use of condom for oral sex is increased to more than 15% of acts. Assuming that treatment of symptomatic infections is prompt, gonorrhoea is unlikely to persist in a heterosexual population even with the addition of anal and oral sex. CONCLUSIONS Our models suggest that oral sex has an important role in sustaining gonorrhoea in a population of MSM by providing a pool of untreated asymptomatic infection. The importance of anal sex or oral sex in sustaining gonorrhoea in a heterosexual population remains uncertain due to the lack of information linking different types of sex acts and transmissibility.
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Affiliation(s)
- B Hui
- The Kirby Institute, UNSW Australia, Sydney, Australia
| | - C K Fairley
- School of Population and Global Health, University of Melbourne, Melbourne, Australia Melbourne Sexual Health Centre, Alfred Health, Melbourne, Australia Australian Research Centre in Sex, Health and Society, La Trobe University, Melbourne, Australia
| | - M Chen
- School of Population and Global Health, University of Melbourne, Melbourne, Australia Melbourne Sexual Health Centre, Alfred Health, Melbourne, Australia Australian Research Centre in Sex, Health and Society, La Trobe University, Melbourne, Australia
| | - A Grulich
- The Kirby Institute, UNSW Australia, Sydney, Australia
| | - J Hocking
- Centre for Women's Health, Gender and Society, University of Melbourne, Melbourne, Australia
| | - G Prestage
- The Kirby Institute, UNSW Australia, Sydney, Australia Australian Research Centre in Sex, Health and Society, La Trobe University, Melbourne, Australia
| | - S Walker
- Melbourne Sexual Health Centre, Alfred Health, Melbourne, Australia
| | - M Law
- The Kirby Institute, UNSW Australia, Sydney, Australia
| | - D Regan
- The Kirby Institute, UNSW Australia, Sydney, Australia
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Althouse BM, Hébert-Dufresne L. Epidemic cycles driven by host behaviour. J R Soc Interface 2014; 11:20140575. [PMID: 25100316 PMCID: PMC4235258 DOI: 10.1098/rsif.2014.0575] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/17/2014] [Indexed: 11/12/2022] Open
Abstract
Host immunity and demographics (the recruitment of susceptibles via birthrate) have been demonstrated to be a key determinant of the periodicity of measles, pertussis and dengue epidemics. However, not all epidemic cycles are from pathogens inducing sterilizing immunity or are driven by demographics. Many sexually transmitted infections are driven by sexual behaviour. We present a mathematical model of disease transmission where individuals can disconnect and reconnect depending on the infectious status of their contacts. We fit the model to historic syphilis (Treponema pallidum) and gonorrhea (Neisseria gonorrhoeae) incidence in the USA and explore potential intervention strategies against syphilis. We find that cycles in syphilis incidence can be driven solely by changing sexual behaviour in structured populations. Our model also explains the lack of similar cycles in gonorrhea incidence even if the two infections share the same propagation pathways. Our model similarly illustrates how sudden epidemic outbreaks can occur on time scales smaller than the characteristic demographic time scale of the population and that weaker infections can lead to more violent outbreaks. Behaviour also appears to be critical for control strategies as we found a bigger sensitivity to behavioural interventions than antibiotic treatment. Thus, behavioural interventions may play a larger role than previously thought, especially in the face of antibiotic resistance and low intervention efficacies.
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Affiliation(s)
| | - Laurent Hébert-Dufresne
- Département de Physique, de Génie Physique, et d'Optique, Université Laval, Québec (Québec), Canada G1V 0A6
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Public health measures to control the spread of antimicrobial resistance in Neisseria gonorrhoeae in men who have sex with men. Epidemiol Infect 2014; 143:1575-84. [PMID: 25275435 DOI: 10.1017/s0950268814002519] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gonorrhoea is one of the most common sexually transmitted infections. The control of gonorrhoea is extremely challenging because of the repeated development of resistance to the antibiotics used for its treatment. We explored different strategies to control the spread of antimicrobial resistance and prevent increases in gonorrhoea prevalence. We used a mathematical model that describes gonorrhoea transmission among men who have sex with men and distinguishes gonorrhoea strains sensitive or resistant to three antibiotics. We investigated the impact of combination therapy, switching first-line antibiotics according to resistance thresholds, and other control efforts (reduced sexual risk behaviour, increased treatment rate). Combination therapy can delay the spread of resistance better than using the 5% resistance threshold. Increased treatment rates, expected to enhance gonorrhoea control, may reduce gonorrhoea prevalence only in the short term, but could lead to more resistance and higher prevalence in the long term. Re-treatment of resistant cases with alternative antibiotics can substantially delay the spread of resistance. In conclusion, combination therapy and re-treatment of resistant cases with alternative antibiotics could be the most effective strategies to prevent increases in gonorrhoea prevalence due to antimicrobial resistance.
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Cost-effectiveness of screening men in Maricopa County jails for chlamydia and gonorrhea to avert infections in women. Sex Transm Dis 2014; 40:776-83. [PMID: 24275727 DOI: 10.1097/olq.0000000000000023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Chlamydia and gonorrhea infections can lead to serious and costly sequelae in women, but sequelae in men are rare. In accordance with the Centers for Disease Control and Prevention guidelines, female jail inmates in Maricopa County (Phoenix area), Arizona, are screened for these infections. Owing to lack of evidence of screening benefits in men, male inmates are tested and treated based on symptoms only. METHODS We developed a probabilistic simulation model to simulate chlamydia and gonorrhea infections in Maricopa County jail male inmates and transmissions to female partners per year. We estimated the cost-effectiveness of screening as the cost per infection averted. Costs were estimated from the perspective of the Maricopa County Department of Public Health and the Correctional Health Services. RESULTS Compared with symptom-based testing and treating strategy, screening male arrestees of all ages and only those 35 years or younger yielded the following results: averted approximately 556 and 491 cases of infection in women at a cost of approximately US $1240 and $860 per case averted, respectively, if screened during physical examination (between days 8 and 14 from entry to jail), and averted approximately 1100 and 995 cases of infections averted at a cost of US $1030 and $710 per infection averted, respectively, if screened early, within 2 to 3 days from entry to jail. CONCLUSIONS Screening of male inmates incurs a modest cost per infection averted in women compared with symptom-based testing. Screening in correctional settings can be used by public health programs to reduce disease burden, sequelae, and associated costs.
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Conflicts of interest during contact investigations: a game-theoretic analysis. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2014; 2014:952381. [PMID: 24982688 PMCID: PMC4052784 DOI: 10.1155/2014/952381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 02/04/2014] [Accepted: 03/06/2014] [Indexed: 11/17/2022]
Abstract
The goal of contact tracing is to reduce the likelihood of transmission, particularly to individuals who are at greatest risk for developing complications of infection, as well as identifying individuals who are in need of medical treatment of other interventions. In this paper, we develop a simple mathematical model of contact investigations among a small group of individuals and apply game theory to explore conflicts of interest that may arise in the context of perceived costs of disclosure. Using analytic Kolmogorov equations, we determine whether or not it is possible for individual incentives to drive noncooperation, even though cooperation would yield a better group outcome. We found that if all individuals have a cost of disclosure, then the optimal individual decision is to simply not disclose each other. With further analysis of (1) completely offsetting the costs of disclosure and (2) partially offsetting the costs of disclosure, we found that all individuals disclose all contacts, resulting in a smaller basic reproductive number and an alignment of individual and group optimality. More data are needed to understand decision making during outbreak investigations and what the real and perceived costs are.
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Low N, Heijne JCM, Herzog SA, Althaus CL. Reinfection by untreated partners of people treated for Chlamydia trachomatis and Neisseria gonorrhoeae: mathematical modelling study. Sex Transm Infect 2014; 90:254-6. [PMID: 24448560 DOI: 10.1136/sextrans-2013-051279] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVES Reinfection after treatment for Chlamydia trachomatis or Neisseria gonorrhoeae reduces the effect of control interventions. We explored the impact of delays in treatment of current partners on the expected probability of reinfection of index cases using a mathematical model. METHODS We used previously reported parameter distributions to calculate the probability that index cases would be reinfected by their untreated partners. We then assumed different delays between index case and partner treatment to calculate the probabilities of reinfection. RESULTS In the absence of partner treatment, the medians of the expected reinfection probabilities are 19.4% (IQR 9.2-31.6%) for C trachomatis and 12.5% (IQR 5.6-22.2%) for N gonorrhoeae. If all current partners receive treatment 3 days after the index case, the expected reinfection probabilities are 4.2% (IQR 2.1-6.9%) for C trachomatis and 5.5% (IQR 2.6-9.5%) for N gonorrhoeae. CONCLUSIONS Quicker partner referral and treatment can substantially reduce reinfection rates for C trachomatis and N gonorrhoeae by untreated partners. The formula we used to calculate reinfection rates can be used to inform the design of randomised controlled trials of novel partner notification technologies like accelerated partner therapy.
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Affiliation(s)
- Nicola Low
- Institute of Social and Preventive Medicine (ISPM), University of Bern, , Bern, Switzerland
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Turner KME, Round J, Horner P, Macleod J, Goldenberg S, Deol A, Adams EJ. An early evaluation of clinical and economic costs and benefits of implementing point of care NAAT tests for Chlamydia trachomatis and Neisseria gonorrhoea in genitourinary medicine clinics in England. Sex Transm Infect 2013; 90:104-11. [PMID: 24273127 PMCID: PMC3932743 DOI: 10.1136/sextrans-2013-051147] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Objectives To estimate the costs and benefits of clinical pathways incorporating a point of care (POC) nucleic acid amplification test (NAAT) for chlamydia and gonorrhoea in genitourinary medicine (GUM) clinics compared with standard off-site laboratory testing. Method We simulated 1.2 million GUM clinic attendees in England. A simulation in Microsoft Excel was developed to compare existing standard pathways of management for chlamydia and gonorrhoea with a POC NAAT. We conducted scenario analyses to evaluate the robustness of the model findings. The primary outcome was the incremental cost-effectiveness ratio. Secondary outcomes included the number of inappropriate treatments, complications and transmissions averted. Results The baseline cost of using the point of POC NAAT was £103.9 million compared with £115.6 million for standard care. The POC NAAT was also associated with a small increase of 46 quality adjusted life years, making the new test both more effective and cheaper. Over 95 000 inappropriate treatments might be avoided by using a POC NAAT. Patients receive diagnosis and treatment on the same day as testing, which may also prevent 189 cases of pelvic inflammatory disease and 17 561 onward transmissions annually. Discussion Replacing standard laboratory tests for chlamydia and gonorrhoea with a POC test could be cost saving and patients would benefit from more accurate diagnosis and less unnecessary treatment. Overtreatment currently accounts for about a tenth of the reported treatments for chlamydia and gonorrhoea and POC NAATs would effectively eliminate the need for presumptive treatment.
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Direct and Indirect Effects of Screening for Chlamydia trachomatis on the Prevention of Pelvic Inflammatory Disease. Epidemiology 2013; 24:854-62. [DOI: 10.1097/ede.0b013e31829e110e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Guy RJ, Natoli L, Ward J, Causer L, Hengel B, Whiley D, Tabrizi SN, Donovan B, Fairley CK, Badman SB, Tangey A, Wand H, Shephard M, Regan DG, Wilson D, Anderson D, Kaldor JM. A randomised trial of point-of-care tests for chlamydia and gonorrhoea infections in remote Aboriginal communities: Test, Treat ANd GO- the "TTANGO" trial protocol. BMC Infect Dis 2013; 13:485. [PMID: 24138699 PMCID: PMC4231474 DOI: 10.1186/1471-2334-13-485] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 10/14/2013] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND High prevalence rates of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) have been reported in Aboriginal people in remote and regional areas of Australia for well over two decades, and repeat positivity rates are high. To interrupt disease transmission and reduce the risk of complications, early diagnosis and treatment is important. However in many remote and regional areas there are long delays between testing for these curable sexually transmissible infections and providing treatment, due to both physical distance from laboratories and difficulties when recalling patients for subsequent management once results are available. Point-of-care (POC) tests have the potential to provide more timely diagnosis, to increase treatment and contact tracing, and in turn reduce CT and NG infection rates. METHODS/DESIGN TTANGO (Test, Treat, ANd GO) is a cross-over cluster randomised controlled trial in 12 regional or remote Australian health services, which predominantly provide clinical services to Aboriginal people. The overall aim of TTANGO is to measure the clinical effectiveness, cost-effectiveness and cultural and operational acceptability of molecular POC testing for CT and NG infection. The primary outcome is repeat positivity at three months after treatment of an initial CT or NG infection. Participating health services will undertake the clinical management of CT and NG under two different modalities for one year each. In the first year, six health services will be randomly assigned to manage these infections under current diagnostic guidelines. The other six will supplement current diagnostic guidelines with POC testing, whereby diagnosis is made and subsequent treatment for those with positive POC tests is offered at the initial consultation. In the second year, the health services will cross over to the opposite management modality. TTANGO will be conducted over four years; 1.5 years of trial initiation and community consultation, 2 years of trial conditions and evaluation, and 6 months of data analysis and feedback. DISCUSSION TTANGO is the first cluster randomised trial of POC testing for CT and NG internationally. The results of this trial will provide crucial information to guide sexual health clinical practice in remote Aboriginal communities and other high prevalence settings. TRIAL REGISTRATION Australian and New Zealand Clinical Trials Registry ACTRN12613000808741.
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Affiliation(s)
- Rebecca J Guy
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Lisa Natoli
- The Kirby Institute, University of New South Wales, Sydney, Australia
- The Burnet Institute, Melbourne, Australia
| | - James Ward
- The Kirby Institute, University of New South Wales, Sydney, Australia
- Baker IDI, Alice Springs, Northern Territory, Alice Springs, Northern Territory, Australia
| | - Louise Causer
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Belinda Hengel
- Apunipima Cape York Health Council, Cairns, Queensland, Australia
| | - David Whiley
- Queensland Paediatric Infectious Diseases (QPID) Laboratory, Queensland Children’s Medical Research Institute, The University of Queensland, Queensland, Australia
| | - Sepehr N Tabrizi
- Department of Microbiology and Infectious Diseases, The Royal Women’s Hospital, Parkville, Victoria, Australia
- Department of Obstetrics and Gynaecology, The Royal Women’s Hospital and Murdoch Childrens Research Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Basil Donovan
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Christopher K Fairley
- Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
- Melbourne Sexual Health Centre, Melbourne, Victoria, Australia
| | - Steven B Badman
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Annie Tangey
- Ngaanyatjarra Health Service, Alice Springs, Northern Territory, Australia
| | - Handan Wand
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Mark Shephard
- Flinders University International Centre for Point of-Care Testing, Flinders University, Adelaide, South Australia, Australia
| | - David G Regan
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - David Wilson
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | | | - John M Kaldor
- The Kirby Institute, University of New South Wales, Sydney, Australia
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Birger RB, Hallett TB, Sinha A, Grenfell BT, Hodder SL. Modeling the impact of interventions along the HIV continuum of care in Newark, New Jersey. Clin Infect Dis 2013; 58:274-84. [PMID: 24140971 DOI: 10.1093/cid/cit687] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The human immunodeficiency virus (HIV) epidemic in Newark, New Jersey, is among the most severe in the United States. Prevalence ranges up to 3.3% in some groups. The aim of this study is to use a mathematical model of the epidemic in Newark to assess the impact of interventions along the continuum of care, leading to virologic suppression. METHODS A model was constructed of HIV infection including specific care-continuum steps. The model was calibrated to HIV/AIDS cases in Newark among different populations over a 10-year period. Interventions applied to model fits were increasing proportions tested, linked and retained in care, linked and adherent to treatment, and increasing testing frequency, high-risk-group testing, and adherence. Impacts were assessed by measuring incidence and death reductions 10 years postintervention. RESULTS The most effective interventions for reducing incidence were improving treatment adherence and increasing testing frequency and coverage. No single intervention reduced incidence in 2023 by >5%, and the most effective combination of interventions reduced incidence by approximately 16% (2%-24%). The most efficacious interventions for reducing deaths were increasing retention, linkage to care, testing coverage, and adherence. Increasing retention reduced deaths by approximately 27% (24%-29%); the most efficacious combination of interventions reduced deaths in 2023 by approximately 52% (46%-57%). CONCLUSIONS Reducing HIV deaths in Newark over a 10-year period may be a realizable goal, but reducing incidence is less likely. Our results highlight the importance of addressing leaks across the entire continuum of care and reinforcing efforts to prevention new HIV infections with additional interventions.
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Affiliation(s)
- Ruthie B Birger
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
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Hui BB, Gray RT, Wilson DP, Ward JS, Smith AMA, Philip DJ, Law MG, Hocking JS, Regan DG. Population movement can sustain STI prevalence in remote Australian indigenous communities. BMC Infect Dis 2013; 13:188. [PMID: 23618061 PMCID: PMC3641953 DOI: 10.1186/1471-2334-13-188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 04/14/2013] [Indexed: 11/25/2022] Open
Abstract
Background For almost two decades, chlamydia and gonorrhoea diagnosis rates in remote Indigenous communities have been up to 30 times higher than for non-Indigenous Australians. The high levels of population movement known to occur between remote communities may contribute to these high rates. Methods We developed an individual-based computer simulation model to study the relationship between population movement and the persistence of gonorrhoea and chlamydia transmission within hypothetical remote communities. Results Results from our model suggest that short-term population movement can facilitate gonorrhoea and chlamydia persistence in small populations. By fixing the number of short-term travellers in accordance with census data, we found that these STIs can persist if at least 20% of individuals in the population seek additional partners while away from home and if the time away from home is less than 21 days. Periodic variations in travel patterns can contribute to increased sustainable levels of infection. Expanding existing STI testing and treatment programs to cater for short-term travellers is shown to be ineffective due to their short duration of stay. Testing and treatment strategies tailored to movement patterns, such as encouraging travellers to seek testing and treatment upon return from travel, will likely be more effective. Conclusion High population mobility is likely to contribute to the high levels of STIs observed in remote Indigenous communities of Australia. More detailed data on mobility patterns and sexual behaviour of travellers will be invaluable for designing and assessing STI control programs in highly mobile communities.
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Affiliation(s)
- Ben B Hui
- The Kirby Institute, University of New South Wales, Sydney, NSW 2052, Australia.
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Owusu-Edusei K, Gift TL, Chesson HW, Kent CK. Investigating the potential public health benefit of jail-based screening and treatment programs for chlamydia. Am J Epidemiol 2013; 177:463-73. [PMID: 23403986 DOI: 10.1093/aje/kws240] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Observational studies have found mixed results on the impact of jail-based chlamydia screen-and-treat programs on community prevalence. In the absence of controlled trials or prospectively designed studies, dynamic mathematical models that incorporate movements in and out of jail and sexual contacts (including disease transmission) can provide useful information. We explored the impact of jail-based chlamydia screening on a hypothetical community's prevalence with a deterministic compartmental model focusing on heterosexual transmission. Parameter values were obtained from the published literature. Two analyses were conducted. One used national values (large community); the other used values reported among African Americans--the population with the highest incarceration rates and chlamydia burden (small community). A comprehensive sensitivity analysis was carried out. For the large-community analysis, chlamydia prevalence decreased by 13% (from 2.3% to 2.0%), and based on the ranges of parameter values (including screening coverage of 10%-100% and a postscreening treatment rate of 50%-100%) used in the sensitivity analysis, this decrease ranged from 0.1% to 58%. For the small-community analysis, chlamydia prevalence decreased by 54% (from 4.6% to 2.1%). Jail-based chlamydia screen-and-treat programs have the potential to reduce chlamydia prevalence in communities with high incarceration rates. However, the magnitude of this potential decrease is subject to considerable uncertainty.
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Affiliation(s)
- Kwame Owusu-Edusei
- Division of STD Preventions, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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Ong JBS, Fu X, Lee GKK, Chen MIC. Comparability of results from pair and classical model formulations for different sexually transmitted infections. PLoS One 2012; 7:e39575. [PMID: 22761828 PMCID: PMC3384672 DOI: 10.1371/journal.pone.0039575] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 05/27/2012] [Indexed: 11/19/2022] Open
Abstract
The "classical model" for sexually transmitted infections treats partnerships as instantaneous events summarized by partner change rates, while individual-based and pair models explicitly account for time within partnerships and gaps between partnerships. We compared predictions from the classical and pair models over a range of partnership and gap combinations. While the former predicted similar or marginally higher prevalence at the shortest partnership lengths, the latter predicted self-sustaining transmission for gonorrhoea (GC) and Chlamydia (CT) over much broader partnership and gap combinations. Predictions on the critical level of condom use (C(c)) required to prevent transmission also differed substantially when using the same parameters. When calibrated to give the same disease prevalence as the pair model by adjusting the infectious duration for GC and CT, and by adjusting transmission probabilities for HIV, the classical model then predicted much higher C(c) values for GC and CT, while C(c) predictions for HIV were fairly close. In conclusion, the two approaches give different predictions over potentially important combinations of partnership and gap lengths. Assuming that it is more correct to explicitly model partnerships and gaps, then pair or individual-based models may be needed for GC and CT since model calibration does not resolve the differences.
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Affiliation(s)
- Jimmy Boon Som Ong
- Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Singapore.
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The role of immunity in the epidemiology of gonorrhoea, chlamydial infection and trichomoniasis: insights from a mathematical model. Epidemiol Infect 2011; 139:1875-83. [PMID: 21299913 DOI: 10.1017/s0950268811000045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Most mathematical models of sexually transmitted infections (STIs) assume that infected individuals become susceptible to re-infection immediately after recovery. This paper assesses whether extending the standard model to allow for temporary immunity after recovery improves the correspondence between observed and modelled levels of STI prevalence in South Africa, for gonorrhoea, chlamydial infection and trichomoniasis. Five different models of immunity and symptom resolution were defined, and each model fitted to South African STI prevalence data. The models were compared in terms of Bayes factors, which show that in the case of gonorrhoea and chlamydial infection, models that allow for immunity provide a significantly better fit to STI prevalence data than models that do not allow for immunity. For all three STIs, estimates of the impact of changes in STI treatment and sexual behaviour are significantly lower in models that allow for immunity. Mathematical models that do not allow for immunity could therefore overestimate the effectiveness of STI interventions.
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