Background: Control strategies for Chlamydia trachomatis (CT) are most effective when targeting people at highest risk. We assessed test acceptance of home-collection test kits offered by short messaging services (SMS) texts, in high-risk young people, i.e. those who had previously tested CT positive (positive indices), or negative reporting more than 3 sex partners (negative indices), and their sexual and social networks.
Methods: Young (16 to 25 years old) heterosexuals who previously tested positive (n=536) or negative (n=536) in our STI clinic received, 3 to 20 months after their initial screening, an SMS inviting them to re-test. They were offered a free home-collection test kit including a genital (men and women) and anorectal (women only) test, and a test kit to pass on to a friend or sex partner (peer). SMS reminders were sent in case of non-response. We assessed proportions of tests requested and returned, peers tested, and positivity. Associations with the individual's initial screening result and other factors were explored using logistic regression.
Results: Of 1072 people invited to retest, 34.4% (n=369) requested a test. Of these, 55.8% (n=206) retested. Overall, retest participation was higher in positive (22%) than in negative indices (16%) (p<0.001); it was also higher in women and in those aged >22 years. Positivity was 13% and 7% in positive and negative indices, respectively. One in 3 retesters also had a peer tested. Of tested peers (n=87), 84% were friends, 31% were first-time testers, and 7% tested positive.
Conclusion: Acceptance of a relatively low-cost strategy for genital and anorectal testing, i.e. using SMS and home-collection test kits, was highest in individuals who previously tested CT positive suggesting that implementation for this group may be considered. By further including a peer-led testing component, undetected CT positives can be identified in the social networks surrounding a high-risk individual.