Chlamydia Positivity in New Orleans Public High Schools, 1996–2005: Implications for Clinical and Public Health Practices

ObjectiveTo describe the trends in chlamydia positivity among New Orleans high school students tested in a schoolwide screening between 1996 and 2005, and to determine factors associated with chlamydia positivity among students during the 10-year period.MethodsBetween school years 1995–1996 and 2004–2005, students in New Orleans public high schools were tested for chlamydia using nucleic acid amplification tests (NAAT) in urine specimens (LCx assay until 1999–2000; BD assay from 2000–2001 to 2004–2005). For each year, we calculated chlamydia positivity by dividing the number of students testing positive by the total number of students tested. Data were analyzed separately by gender. Logistic regressions were performed to determine independent predictors of chlamydia positivity during the 10-year period.ResultsBetween 1996 and 2005, the average chlamydia positivity was 7.0% (95% confidence interval 6.6–7.4) in boys and 13.1% (95% confidence interval 12.6–13.7) in girls (P < .001). Chlamydia detection increased with the switch from LCx to BD assay. In multivariate analyses, chlamydia positivity among boys and girls was significantly associated with age, black race, and gonorrhea coinfection. Additionally, positivity was significantly different by school year among boys (P = .03) and by NAAT used among girls (P = .008).ConclusionsThe trends in chlamydia positivity observed between 1996 and 2005 more likely reflected a high and stable prevalence of chlamydia in the New Orleans school-age adolescent population. Any benefit of screening on individuals tested was likely to be mitigated by participants' uninterrupted social interactions with the dynamic forces that sustain the sexual transmission of chlamydia in the population.