DISCUSSION
infection, chlamydia, HIV among adolescent girls, trichomoniasis, gonorrhea, decrease loss
STIS, INFECTION, TRICHOMONIASIS, SEQUELAE, GONORRHEA
We found a very high prevalence of curable STIs among adolescents and young adults in a predominantly rural area of KwaZulu-Natal, South Africa. This study confirms the acceptability of home-based STI specimen collection among adolescents and young adults, as more than 90% of study participants who were offered STI testing provided specimens. The prevalence of STI was significantly higher among female than male participants overall, even when adjusted for age and other demographic factors. The sex difference in prevalence was most pronounced for trichomoniasis and chlamydia; prevalence of gonorrhea was similar between male and female participants. Participants residing in urban/periurban areas were more likely to have an STI than those residing in rural areas. Despite multiple contact attempts by study staff, only 1 of 3 participants who tested positive for an STI was treated within 7 days. Difficulties in follow-up contact compounded by a low (6.8%) treatment refusal indicates a need for a robust tracking system and strategies to maximize treatment reach, and underscores the need for point-of-care STI tests to enable same-day treatment and decrease loss to follow-up.In this cohort, women had a higher STI prevalence than men overall, particularly trichomoniasis and chlamydia. These results mirror both national-level estimates of STI prevalence in South Africa and previous studies among adolescents and young adults in rural KwaZulu-Natal; in both cases, chlamydia prevalence was over twice as high among women than men.We found a substantially higher prevalence of chlamydia and gonorrhea in this cohort than in a previous study conducted in the same geographic area in 2016 to 2017.We additionally found that young men and women residing in urban or periurban areas were more likely to have an STI than those residing in rural areas, even after adjustment for other demographic factors, including age, employment status, and migration history. A recent study evaluating transmissible HIV among adolescent girls and young women exposed to the PEPFAR-supported DREAMS intervention, conducted at the same study site, similarly found that urban/periurban residence was associated with transmissible HIV.Despite the robust infrastructure of the randomized trial and the long-standing experience of AHRI conducting research that is strongly linked with public sector health clinics in this area, less than half of the participants with STIs were able to be treated within 7 days, and less than two-thirds within 4 weeks. Those living in urban areas were less likely to be treated within 7 days, possibly because of a higher rate of employment or difficulty tracking participants. Those in the highest socioeconomic tertile were more likely to be treated within 7 days, which may reflect either greater access to technology such as mobile phones for contact by study staff, or easier access to clinic for treatment. Diagnostic testing for STIs remains inaccessible in most resource-limited settings, because of high costs and a need for laboratory infrastructure; when STI testing is available in such settings, it is often restricted to centralized laboratories. For this study, STI specimens were transported from the rural study site to a centralized research laboratory in Durban (approximately 230 km away), resulting in an extended time from specimen collection to test result. Loss to follow-up increases with extensions in test turnaround time, and delays in treatment lead to the potential for ongoing transmission and increased risk for sequelae of untreated infection. A study assessing community-based STI testing for adolescents and young adults in Zimbabwe found that, even with an expected 90-minute time to result, only 67% of those with positive test results were treated.Our assessment of factors associated with STIs was limited by the scope of demographic data available and lack of contemporaneous data on symptoms and sexual risk behavior. The trial did not include study-specific questionnaires at the time of enrollment to measure the real-world effect of offering the combination of interventions. Demographics were thus linked from annual HDSS household surveys. These surveys include annually updated, individual- (e.g., education level, employment status) and household-level (e.g., socioeconomic status, rural vs. urban residence) data. Despite a lack of detail regarding sexual risk behavior, the HDSS data provide information on several important demographics that are standardized across prior studies and have previously been found to be associated with STIs and HIV in this area.In conclusion, we found a very high prevalence of curable STIs among adolescent and young adult men and women, which is higher than in a previous study 5 years ago, in a predominantly rural area with high HIV incidence in KwaZulu-Natal, South Africa. The prevalence of STI was higher among women than men and among those residing in urban/periurban areas than those residing in rural areas. Despite multiple attempts by study staff, fewer than two-thirds of participants with positive test results were able to be treated within 4 weeks. These results highlight the need for implementation of STI testing and treatment programs in settings with both STIs and HIV, as well as the need for point-of-care STI tests to allow immediate treatment for those who test positive and decrease loss to follow-up.