The impact of thinking and doing on chlamydia transmission (iMPaCT)

Chlamydia is the most commonly reported STI in the Netherlands and the number of reported cases has been increasing in the past few years. Control of this infection is of public health importance, because chlamydia infections are associated with increased risk of serious reproductive consequences, such as pelvic inflammatory disease (PID), ectopic pregnancy and infertility. However, control of chlamydia has proven to be challenging; reasons for this might be high re-infection rates after treatment. Therefore, behaviour change after a diagnosis might be vital to reduce re-infection rates. In addition, because most people are unaware of their infection, preventive health actions (such as using condoms) depend on psychological determinants, making the incorporation of such determinants in mathematical models especially important in this field. Ultimately, the data collected in the clinical study will be used to parameterise a mathematical model, which will provide valuable information for public health policy makers to guide which intervention measures should be prioritised and conducted in the future.

We aim to study the link between behavioural and psychological determinants and chlamydia (re-)infection, and to develop mathematical models for curable STI incorporating these determinants to be able to better estimate the impact of interventions.

Four time points:

1. Baseline

2. 1 month follow-up

3. 6-months follow-up

4. 1 year follow-up

The aim of this observational study is to collect data on sexual behaviour and psychological determinants from people visiting STI clinics. Participants are enrolled for a year, and questionnaires are administrated at four time points: at baseline, 3-4 weeks, 6 months and at one year follow-up. To be able to link behavioural and psychological determinants to (re-)infections, participants will be tested for chlamydia at enrolment and at 6 months follow-up.