title: A Method to Estimate the Size and Characteristics of HIV-positive Populations Using an Individual-based Stochastic Simulation Model.
abstract: It is important not only to collect epidemiologic data on HIV but to also fully utilize such information to understand the epidemic over time and to help inform and monitor the impact of policies and interventions. We describe and apply a novel method to estimate the size and characteristics of HIV-positive populations. The method was applied to data on men who have sex with men living in the UK and to a pseudo dataset to assess performance for different data availability. The individual-based simulation model was calibrated using an approximate Bayesian computation-based approach. In 2013, 48,310 (90% plausibility range: 39,900-45,560) men who have sex with men were estimated to be living with HIV in the UK, of whom 10,400 (6,160-17,350) were undiagnosed. There were an estimated 3,210 (1,730-5,350) infections per year on average between 2010 and 2013. Sixty-two percent of the total HIV-positive population are thought to have viral load <500 copies/ml. In the pseudo-epidemic example, HIV estimates have narrower plausibility ranges and are closer to the true number, the greater the data availability to calibrate the model. We demonstrate that our method can be applied to settings with less data, however plausibility ranges for estimates will be wider to reflect greater uncertainty of the data used to fit the model.
authors.affiliation: From the aResearch Department of Infection and Population Health, UCL, London, United Kingdom; bStichting HIV Monitoring, Amsterdam, The Netherlands; cINSERM, Centre INSERM U897, Bordeaux, France; dDepartment of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom; eDepartment of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden; fDepartment of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden; gEuropean Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden; hCEEISCAT, Generalitat de Catalunya, Barcelona, Spain; iWHO Regional Office for Europe, Copenhagen, Denmark; jInstitute of Clinical Trials and Methodology, UCL, London, United Kingdom; kDivision of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, Zurich, Switzerland; lResearch Department of Primary Care and Population Health, UCL, London, United Kingdom; mCHIP @ Department of Infectious Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; nDepartment of Hygiene, Epidemiology and Medical Statistics, University of Athens Medical School, Athens, Greece; oUCL Institute of Child Health, UCL, London, United Kingdom; and pPublic Health England, London, United Kingdom.
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Nakagawa
authors.forename: Ard
authors.initials: A
authors.lastname: van Sighem
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Thiebaut
authors.forename: Colette
authors.initials: C
authors.lastname: Smith
authors.forename: Oliver
authors.initials: O
authors.lastname: Ratmann
authors.forename: Valentina
authors.initials: V
authors.lastname: Cambiano
authors.forename: Jan
authors.initials: J
authors.lastname: Albert
authors.forename: Andrew
authors.initials: A
authors.lastname: Amato-Gauci
authors.forename: Daniela
authors.initials: D
authors.lastname: Bezemer
authors.forename: Colin
authors.initials: C
authors.lastname: Campbell
authors.forename: Daniel
authors.initials: D
authors.lastname: Commenges
authors.forename: Martin
authors.initials: M
authors.lastname: Donoghoe
authors.forename: Deborah
authors.initials: D
authors.lastname: Ford
authors.forename: Roger
authors.initials: R
authors.lastname: Kouyos
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lodwick
authors.forename: Jens
authors.initials: J
authors.lastname: Lundgren
authors.forename: Nikos
authors.initials: N
authors.lastname: Pantazis
authors.forename: Anastasia
authors.initials: A
authors.lastname: Pharris
authors.forename: Chantal
authors.initials: C
authors.lastname: Quinten
authors.forename: Claire
authors.initials: C
authors.lastname: Thorne
authors.forename: Giota
authors.initials: G
authors.lastname: Touloumi
authors.forename: Valerie
authors.initials: V
authors.lastname: Delpech
authors.forename: Andrew
authors.initials: A
authors.lastname: Phillips
mesh_terms: D001499:Bayes Theorem; D001727:Bisexuality; D003198:Computer Simulation; D058872:Epidemics; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology*; D018451:Homosexuality, Male; D006801:Humans; D015994:Incidence; D008297:Male; D015233:Models, Statistical; D013269:Stochastic Processes; D006113:United Kingdom; D019562:Viral Load