Background:
The Philadelphia High School STD Screening Program (HSSSP) has provided a yearly educational program and voluntary, confidential screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) at all public Philadelphia high schools since the 2002-2003 school year.

Objective:
To understand the temporal trends in positivity rates and participation rates after 4 consecutive years of the HSSSP and to determine if these trends are associated with any student or high-school characteristics.


Method:
Positivity rates were calculated each year and stratified by factors such as student sex, student age, and school type. Linear regression was used to identify characteristics associated with declining positivity.


Result:
Preliminary analyses of the first 3 years of HSSSP show that the CT positivity rate among participating high school students declined from 4.9% in 2002-2003 to 3.7% in 2004-2005, a 24% decline in positivity and a 35% decline in the number of positive cases. There was a larger decline among female students than male students. Participation declined slightly from 19,713 students submitting sample in 2002-2003 to 16,378 samples in 2004-2005. In every year of the program, more than 99% of infected students were treated. At the same time, total reported citywide CT morbidity declined from a peak of 17,747 cases in 2003 to a projected 15,189 in 2005. Additional results will be presented on GC test results, data from the 2005-2006 school year, and analyses stratified by high-school type.

Conclusion:
A sustained high-school based screening program has yielded significant declines in positivity rates over time and a temporally associated decline in total citywide morbidity.

Implications:
STD programs should consider high school-based screening/education programs as a potentially important adjunct to existing efforts to reduce the prevalence of CT in the populations they serve.