Roughly 1 in 21 sexually active women ages 24 and under are infected with chlamydia, with rates higher among minorities, according to data from the latest National Health and Nutrition Examination Survey (NHNES). The most common notifiable disease in the United States, 1.4 million cases were reported in 2012, yet screening rates for the sexually transmitted infection remains low.

The U.S. Preventive Services Task Force recommends healthcare providers routinely screen all sexually active young women aged 24 and younger, however fewer than half of this population are tested for chlamydia each year.

Younger women and minorities are at greatest risk of chlamydial infection, with its prevalence decreasing by age. The overall rate is 1.7% among sexually active persons aged 14 to 39 years, but increases to 4.7% in women ages 14 to 24, and 13.5% in non-Hispanic black women under age 25. Compared with non-Hispanic white females, rates are 7 times higher in non-Hispanic black females and 3 times higher in Mexican-American women.

Other risk factors include having multiple sex partners and not using condoms. Unlike prior studies, however, the use of oral contraceptives or DepoProvera was not associated with greater risk.

Citation: Torrone E, Papp J, Weinstock H. Prevalence of chlamydia trachomatis genital infection among persons aged 14-39 years – United States, 2007-2012. MMWR Morb Mortal Wkly Rep. 2014;63(38):834-8.

Commentary: The consequences of untreated chlamydia infections are large, including the development of pelvic inflammatory disease (PID) with consequent increased risk of infertility, chronic pelvic pain, and ectopic pregnancy. It is well proven that routine screening decreases the incidence of PID. The prevalence of chlamydia infections remains astonishingly high, and routine screening yields frequent positive findings, leading to treatment of both patient and their partner. It is important to remember that screening does not require performing a pelvic exam, and is most easily accomplished using a urine sample sent for a nucleic acid amplification test (NAAT). —Neil Skolnik, MD