Background:
Repeat infection with Chlamydia trachomatis (Ct) is common among women and associated with serious, long-term sequelae. Sex with untreated male partners is a frequent cause. Universal Ct screening is performed in New York City (NYC) STD clinics. CDC treatment guidelines (2002) recommend re-screening women for Ct following an infection.

Objective:
Describe ‘repeat infection' (Ct case in the same woman reported >30 days after initial Ct report) among NYC females to guide potential intervention strategies.

Method:
Demographics and gonorrhea (GC) co-infection were examined for women aged 10-29 with >1 case of Ct in the NYC STD surveillance registry between January 2000-June 2005. Repeat infection was assessed for one year following infection. Providers working outside NYC STD clinics were defined as ‘private providers'.

Result:
In 5˝ years, 91,979 women were reported with 117,792 cases of Ct. Among 17,128 women reported in 2000, 14% had repeat infection in the first year (32% of those detected by 3 months); among 21,142 women reported in July 2003-June 2004, 13% had repeat infection in the first year (29% by 3 months). Repeat infection was highest among 10-14 and 15-19 y.o. girls and among cases initially seen by private providers. In multivariate analysis of July 2003-June 2004, private provider report (OR 1.8,); Black, non-Hispanic race/ethnicity (OR 2.1); younger age groups versus 25-29 y.o. (OR ~2.0); and GC co-infection (OR 1.4) significantly predicted repeat infection.

Conclusion:
One-third of reported repeat infections were documented within three months of infection. As most reports originated from private providers, they should be targeted for education regarding sex partner treatment. The age of those at highest risk suggests concentrating on pediatricians.

Implications:
Repeat infection is likely under-ascertained due to failure to re-screen or report. Adolescent-centered case management and partner notification could reduce repeat infection; however, limited resources may be a constraint.