How Often Should We be Screening Adolescents for Chlamydia and STDs?
Abstract & Commentary
Synopsis: It has been recommended that it is necessary to screen sexually active adolescent females as often as every six months because of a high rate of infection and reinfection with chlamydia in such young populations. Such a broad recommendation may not be generalizable to all sexually active adolescent females because many live in low-prevalence chlamydial areas or have few or no risk factors for acquisition of STDs.
Source: Burstein GR, et al. Incidence of Chlamydia trachomatis infections among inner-city adolescent females. JAMA 1998;280:521-526.
A prospective longitudinal study to describe the prevalence and incidence of chlamydial infection among adolescent females was undertaken by Burstein and associates at Johns Hopkins in order to define the appropriate interval for chlamydial screening and to define risk factors for chlamydial acquisition in order to develop screening criteria. Consecutive sexually active, largely poor African American (98%), adolescent females aged 12-19 years attending STD, family planning, and school-based clinics in the Baltimore city area were entered into the study. Over a 33-month period, there were 3202 adolescent females who made 5360 visits more than 30 days apart, with the mean number of visits per patient being two (Burstein et al used 30 days to define the period for an "incident infection"). Chlamydia was identified on either endocervical specimens if a pelvic exam was warranted or by first void urine using PCR. During the study period, 29% had at least one positive chlamydial test, with the mean time to first positive chlamydia being 7.2 months and to reinfection (after having a positive test and being appropriately treated) being only 6.3 months. Burstein et al were unable to identify those individuals with most of the infections using the usual STD risk factors, including reason for visit, clinic type, history of STDs, multiple or new partners, or poor compliance with condom use.
Comment by Mary Ann Shafer, MD, FAAP
Sexually active adolescent females have a high rate of chlamydial infection. However, the rate for all populations, including adolescents, has been decreasing over the past few years. There remain some areas in the country, such as Baltimore, where the prevalence remains extraordinarily high. With the advent of amplified nucleic acid techniques (PCR, LCR) that can yield highly sensitive and specific test profiles when applied to noninvasive urine specimens, we now have a much greater chance to accurately define the true problem of chlamydial infection since we are no longer dependent upon pelvic exams for females or urethral swabs in males to obtain specimens. Urine tests will also make it easier to screen all sexually active youth as often as deemed appropriate in a number of clinical and nonclinical settings to treat infections successfully with appropriate antibiotics and finally to afford us the chance of eliminating chlamydia as a risk to young women.
Although this study did show that among poor youth in Baltimore, chlamydial screening should be broad-based and as frequent as every six months, Burstein et al fail to discuss the risk of infection and possible implications for the youth in the rest of the country, where the prevalence rate for chlamydia is between 5-10% and dropping. While I agree with more frequent screening among adolescents in high-risk prevalence areas, I disagree that Burstein et al have convinced us that this recommendation should also apply to all adolescents. It could be argued that the same study needs to be done in a lower prevalence population in order to have evidence to support or refute the current recommendation by most professional health organizations that all sexually active adolescents be screened for chlamydia and gonorrhea and have a Pap smear annually. The main take-home message for the practicing clinician is that we now can easily and accurately screen for chlamydia using a noninvasive screening test applied to urine.