• Double trouble: modelling the impact of low risk perception and high-risk sexual behaviour on chlamydia transmission.

      van Wees, Daphne A; den Daas, Chantal; Kretzschmar, Mirjam E E; Heijne, Janneke C M (2018-04)
      Risk perception plays an important role in testing behaviour for sexually transmitted infections, but is rarely included in mathematical models exploring the impact of testing. We explored the impact of incorporating sexual behaviour (SB), risk perception (RP) and differential testing uptake in SB-RP groups on prevalence, using chlamydia as an example. We developed a pair model with a susceptible-infected-susceptible structure representing heterosexuals aged 16-26 years. The effect of testing on chlamydia prevalence was compared between a model with only SB (SB model) and a model with SB and RP (SB-RP model). In the SB-RP model, a scenario without differential testing uptake in SB-RP groups was compared to scenarios with differential testing uptake in SB-RP groups. Introducing testing into the SB-RP model resulted in a slightly smaller reduction in chlamydia prevalence (-38.0%) as compared to the SB model (-40.4%). In the SB-RP model, the scenario without differential testing uptake in SB-RP groups overestimated the reduction in chlamydia prevalence (with 4.8%), especially in the group with high SB and low RP (19.8%). We conclude that mathematical models incorporating RP and differential testing uptake in SB-RP groups improve the impact assessment of testing and treatment on chlamydia prevalence.
    • Identifying STI risk groups based on behavioral and psychological characteristics among heterosexuals during the COVID-19 pandemic.

      van Wees, Daphne A; Godijk, Noortje G; den Daas, Chantal; Kretzschmar, Mirjam E E; Heijne, Janneke C M (2021-08-31)
    • The impact of STI test results and face-to-face consultations on subsequent behavior and psychological characteristics.

      van Wees, Daphne A; Drissen, Meggie M C M; den Daas, Chantal; Heijman, Titia; Kretzschmar, Mirjam E E; Heijne, Janneke C M (2020-07-11)
    • Longitudinal Patterns of Sexually Transmitted Infection Risk Based on Psychological Characteristics and Sexual Behavior in Heterosexual Sexually Transmitted Infection Clinic Visitors.

      van Wees, Daphne A; Heijne, Janneke C M; Basten, Maartje; Heijman, Titia; de Wit, John; Kretzschmar, Mirjam E E; den Daas, Chantal (2020-03-01)
    • Modelling the impact of tailored behavioural interventions on chlamydia transmission.

      van Wees, Daphne A; den Daas, Chantal; Kretzschmar, Mirjam E E; Heijne, Janneke C M (2021-01-25)
    • A Multidimensional Approach to Assess Infectious Disease Risk: Identifying Risk Classes Based on Psychological Characteristics.

      van Wees, Daphne A; Heijne, Janneke C M; Heijman, Titia; Kampman, Karlijn C J G; Westra, Karin; de Vries, Anne; de Wit, John; Kretzschmar, Mirjam E E; den Daas, Chantal (2019-05-30)
    • Study protocol of the iMPaCT project: a longitudinal cohort study assessing psychological determinants, sexual behaviour and chlamydia (re)infections in heterosexual STI clinic visitors.

      van Wees, Daphne A; Heijne, Janneke C M; Heijman, Titia; Kampman, Karlijn C J G; Westra, Karin; de Vries, Anne; Kretzschmar, Mirjam E E; den Daas, Chantal (2018-11-13)
      Chlamydia trachomatis (chlamydia), the most commonly reported sexually transmitted infection (STI) in the Netherlands, can lead to severe reproductive complications. Reasons for the sustained chlamydia prevalence in young individuals, even in countries with chlamydia screening programs, might be the asymptomatic nature of chlamydia infections, and high reinfection rates after treatment. When individuals are unaware of their infection, preventive behaviour or health-care seeking behaviour mostly depends on psychological determinants, such as risk perception. Furthermore, behaviour change after a diagnosis might be vital to reduce reinfection rates. This makes the incorporation of psychological determinants and behaviour change in mathematical models estimating the impact of interventions on chlamydia transmission especially important. Therefore, quantitative real-life data to inform these models is needed. A longitudinal cohort study will be conducted to explore the link between psychological and behavioural determinants and chlamydia (re)infection among heterosexual STI clinic visitors aged 18-24 years. Participants will be recruited at the STI clinics of the public health services of Amsterdam, Hollands Noorden, Kennemerland, and Twente. Participants are enrolled for a year, and questionnaires are administrated at four time points: baseline (before an STI consultation), three-week, six-month and at one-year follow-up. To be able to link psychological and behavioural determinants to (re)infections, participants will be tested for chlamydia at enrolment and at six-month follow-up. Data from the longitudinal cohort study will be used to develop mathematical models for curable STI incorporating these determinants to be able to better estimate the impact of interventions. This study will provide insights into the link between psychological and behavioural determinants, including short-term and long-term changes after diagnosis, and chlamydia (re)infections. Our mathematical model, informed by data from the longitudinal cohort study, will be able to estimate the impact of interventions on chlamydia prevalence, and identify and prioritise successful interventions for the future. These interventions could be implemented at STI clinics tailored to psychological and behavioural characteristics of individuals. Dutch Trial Register NTR-6307 . Retrospectively registered 11-nov-2016.
    • Who drops out and when? Predictors of non-response and loss to follow-up in a longitudinal cohort study among STI clinic visitors.

      van Wees, Daphne A; den Daas, Chantal; Kretzschmar, Mirjam E E; Heijne, Janneke C M (2019-01-01)