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Making it count 2: Risk underestimation, high-risk sexual behavior episodes and estimating the impact of tailored interventions, a novel approach to HIV elimination

Projectomschrijving

De meeste nieuwe hiv infecties worden gevonden bij mannen die seks hebben met mannen (MSM). Infecties kunnen worden voorkomen door interventies, zoals het gebruik van pre-exposure prophylaxe (PrEP), in te zetten in periodes van hoog risicogedrag.

Om de timing van interventies te verbeteren hebben we in Making It Count 1 in kaart gebracht hoe seksueel risicogedrag verandert gedurende de levensloop van MSM.

Het huidige doel is inzicht krijgen in de duur en frequentie van korte periodes van individueel hoog risico. Daarnaast onderzoeken we of MSM zich bewust zijn van de risico's van hun gedrag en hoe risicoperceptie verandert over tijd.

De uitkomsten gebruiken wij in een wiskundig model om te onderzoeken hoe de verspreiding van hiv wordt beïnvloed door periodes van hoog risicogedrag en de inschatting van het eigen risico. Het model verduidelijkt op welke momenten PrEP zou moeten worden ingezet om de verspreiding van hiv zo effectief mogelijk tegen te gaan.

Lees meer informatie over hiv en de onderzoeken op onze themapagina over hiv

Producten

Titel: Time for change: Transitions between HIV risk levels and determinants of behavior change in men who have sex with men
Auteur: Basten MG, van Wees DA, Matser A, Boyd A, Rozhnova G, den Daas C, Kretzschmar ME, Heijne JC
Magazine: PLoS ONE
Titel: The Rhythm of Risk: Sexual Behaviour, PrEP Use and HIV Risk Perception Between 1999 and 2018 Among Men Who Have Sex with Men in Amsterdam, The Netherlands.
Auteur: Basten M, den Daas C, Heijne JCM, Boyd A, Davidovich U, Rozhnova G, Kretzschmar M, Matser A.
Magazine: Aids & Behavior

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Eindverslag

De meeste nieuwe HIV infecties worden gevonden bij mannen die seks hebben met mannen (MSM). Infecties kunnen worden voorkomen door interventies, zoals het gebruik van pre-exposure prophylaxe (PrEP), in te zetten in periodes van hoog risicogedrag. Het doel van dit project was inzicht krijgen in de duur en frequentie van korte periodes van individueel hoog risico. Daarnaast onderzochten we of MSM zich bewust zijn van de risico's van hun gedrag en hoe risicoperceptie verandert over tijd. We vonden een aantal voorspellers voor toename van risico op korte termijn, zoals een soa diagnose in de laatste 6 maanden en een hoge risico perceptie. Deze voorspellende variabelen zouden gebruikt kunnen worden om PrEP op de juiste momenten aan te bieden. We zagen dat risico perceptie onder MSM over de jaren is verandert, mogelijk als reactie op veranderingen in de epidemiologische situatie en behandelingsmogelijkheden van hiv.

De meeste nieuwe HIV infecties worden gevonden bij mannen die seks hebben met mannen (MSM). Infecties kunnen worden voorkomen door interventies, zoals het gebruik van pre-exposure prophylaxe (PrEP), in te zetten in periodes van hoog risicogedrag. Om de timing van interventies te verbeteren hebben we in Making It Count 1 in kaart gebracht hoe seksueel risicogedrag verandert gedurende de levensloop van MSM. Het huidige doel is inzicht krijgen in de duur en frequentie van korte periodes van individueel hoog risico. Daarnaast onderzoeken we of MSM zich bewust zijn van de risico's van hun gedrag en hoe risicoperceptie verandert over tijd. De uitkomsten gebruiken wij in een wiskundig model om te onderzoeken hoe de verspreiding van HIV wordt beïnvloed door periodes van hoog risicogedrag en de inschatting van het eigen risico. Het model verduidelijkt op welke momenten PrEP zou moeten worden ingezet om de verspreiding van HIV zo effectief mogelijk tegen te gaan.

Samenvatting van de aanvraag

HIV transmission continues among men who have sex with men (MSM) in the Netherlands, despite the availability of effective interventions. A reduction in HIV spread is expected with the introduction of pre-exposure prophylaxis (PrEP), but risk compensation and lack of adherence due to decreasing risk perception might eventually hamper its impact on population level. In general, tailoring preventive interventions to specific periods of high-risk and by targeting MSM who underestimate their own risk can increase their effectiveness. Time-tailored interventions will be particularly important for PrEP implementation to prevent high costs, medication overuse, and lack of adherence in the population. A prerequisite for the development of time-tailored interventions is a close understanding of changes in sexual risk behavior and perception over time, the interaction between behavior and perception, and its impact on the spread of HIV and other sexually transmitted infections. In our pilot-study funded by ZonMw in 2015 we examined longitudinal changes in sexual behavior predictive of HIV acquisition from sexual debut onwards at the population level. We identified three typical linear trajectories of sexual risk behavior across the life course: Low risk, Falling high risk, and Rising high risk. This knowledge can be used for designing population level interventions, but does not give insight in individual changes in risk behavior on a shorter time scale. Mathematical modelling results from our pilot study and other studies suggest however that short-term episodic changes in sexual risk behavior may have a large impact on HIV transmission dynamics and effectiveness of interventions. Consequently, the objectives of the current study are to 1) study the frequency and duration of episodes of high-risk sexual behavior with increased risk of acquiring HIV, 2) study longitudinal changes in perceived risk of HIV; 3) examine synchrony between longitudinal changes in risk behavior and risk perception, and investigate how discrepancies between risk behavior and risk perception are related to subsequent HIV infection; and 4) study the impact of episodes of high-risk sexual behavior, risk perception and time-tailored implementation of PrEP on HIV transmission dynamics. Data from over 800 HIV-negative MSM who participated between 2007-2018 in the Amsterdam Cohort Studies on HIV and AIDS (ACS) will be used. The ACS is a population-based open cohort initiated in 1984. At each biannual visit, MSM are asked to fill in a questionnaire about their sexual behavior and their perceived risk of having acquired HIV in the past six months and they are tested for HIV and STI. We will use the comprehensive sexual behavior risk score predictive of HIV acquisition, which was developed in the pilot study, to study episodes of high-risk sexual behavior. Using Hidden Markov Modeling (HMM), we will derive information on how often individuals transition between different levels of sexual risk behavior over time and how long they stay at a high risk level. The same method will also be used to study changes in risk perception over time. Subsequently, transitions in levels of sexual risk behavior and risk perception will be analyzed together in a joint HMM. This joint model will provide insights in the possible co-occurrence of changes in sexual risk behavior and risk perception, and will enable us to identify whether and when discrepancies between behavior and perception arise. Based on this model we will be able to distinguish between MSM who underestimate their risk, overestimate their risk, and MSM who have a realistic risk perception. We will test the impact of underestimating one’s risk by studying the association between risk underestimation and the acquisition of HIV infection in a Poisson regression model. Subsequently, we will develop a mathematical model for HIV transmission in which we will incorporate the findings from our statistical analyses on episodic sexual risk behavior and change in risk perception to test the impact of these phenomena on HIV transmission dynamics. We will study how changes in sexual risk behavior and risk perception affect the effectiveness of PrEP in reducing HIV incidence. The proposed project is multidisciplinary in that it combines social sciences, statistics, epidemiology, and mathematical modeling. The project is innovative in 1) studying longitudinal changes in sexual risk behavior and perceived risk of HIV simultaneously using detailed behavioral data over a 10-year follow-up period, and 2) incorporating change in risk behavior and risk perception in a mathematical model to study the impact of PrEP on HIV transmission dynamics. Our findings have the potential to improve the cost-effectiveness of HIV prevention strategies, because we will identify MSM who should be targeted with preventive interventions at the right time point in their sexual career in order to have the highest impact on HIV spread.

Onderwerpen

Kenmerken

Projectnummer:
522004009
Looptijd: 100%
Looptijd: 100 %
2018
2021
Onderdeel van programma:
Gerelateerde subsidieronde:
Projectleider en penvoerder:
Prof. dr. M.E.E. Kretzschmar
Verantwoordelijke organisatie:
Universitair Medisch Centrum Utrecht