Mathematical modeling study of school-based chlamydia screening: potential impact on chlamydia prevalence in intervention schools and surrounding communities

BACKGROUND: Chlamydia screening in high schools offers a way to reach adolescents outside of a traditional clinic setting. Using transmission dynamic modeling, we examined the potential impact of high-school-based chlamydia screening programs on the burden of infection within intervention schools and surrounding communities, under varying epidemiological and programmatic conditions. METHODS: A chlamydia transmission model was calibrated to epidemiological data from three different settings. Philadelphia and Chicago are two high-burden cities with existing school-based screening programs. Rural Iowa does not have an existing program but represents a low-burden setting. We modeled the effects of the two existing programs to analyze the potential influence of program coverage and student participation. All three settings were used to examine a broader set of hypothetical programs with varying coverage levels and time trends in participation. RESULTS: In the modeled Philadelphia program, prevalence among the intervention schools’ sexually active 15–18 years old population was 4.34% (95% credible interval 3.75–4.71%)after 12 program years compared to 5.03% (4.39–5.43%) in absence of the program. In the modeled Chicago program, prevalence was estimated as 5.97% (2.60–7.88%) after 4 program years compared to 7.00% (3.08–9.29%) without the program. In the broader hypothetical scenarios including both high-burden and low-burden settings, impact of school-based screening programs was greater in absolute terms in the higher-prevalence settings, and benefits in the community were approximately proportional to population coverage of intervention schools. Most benefits were garnered if the student participation did not decline over time. CONCLUSIONS: Sustained high student participation in school-based screening programs and broad coverage of schools within a target community are likely needed to maximize program benefits in terms of reduced burden of chlamydia in the adolescent population.