Rescreening can stem repeat chlamydia

You have just delivered some bad news to the adolescent female patient in the exam room: Her test for chlamydial infection proved positive. After you have provided the appropriate counseling about partner treatment and prescribed drug therapy, what is your next course of action?

If you are planning to rescreen the patient within three to six months, you are tapping into a prevention effort that may well stem repeat chlamydial infection in young women, termed "an urgent public health priority" by authors of a recently published analysis of a population-based sexually transmitted disease (STD) registry in Washington state.1

One of the major findings of the study was that repeat chlamydial infection was common, especially for young women, says Fujie Xu, MD, PhD, a researcher in the Atlanta-based Centers for Disease Control and Prevention (CDC) National Center for HIV, STD, and TB Prevention, Division of STD Prevention.

According to the study’s findings, among 32,698 women with an appropriately treated initial chlamydial infection during 1993-1998, 15% developed one or more repeat infections during a mean follow-up time of 3.4 years. Among women younger than age 20 at the time of initial infection, 6% were reinfected by six months, 11% by one year, and 17% by two years. Young age was the strongest predictor for one and two or more repeat infections after controlling for the length of follow-up and other variables, researchers reported.

Why is it so important to stem chlamydia? Although it is often asymptomatic, chlamydial infection can result in pelvic inflammatory disease, infertility, and ectopic pregnancy. It also may result in adverse pregnancy outcomes, such as neonatal conjunctivitis and pneumonia. In addition, recent research has shown that women infected with chlamydia have a three- to fivefold increased risk of acquiring HIV.2

County uses three-month tests

To stem the spread of chlamydia in King County, WA, local health department officials encourage women to return to their providers or clinics to be retested three months after treatment. The department has implemented a similar rescreening program for gonorrhea.

County public health officials began the prevention effort two years ago by simply advising infected women to return for retesting after three months. But as of spring 2001, tracking procedures and other measures were initiated in an attempt to make sure rescreening occurs, says H. Hunter Handsfield, MD, director of the STD Control Program at Public Health — Seattle and King County in Seattle, and professor of medicine at the University of Washington, also in Seattle.

The department contacts patients from the public health STD clinic if they have not returned for rescreening by four months, says Handsfield. For those women with chlamydial infection diagnosed elsewhere in King County, the health care provider gets a letter reminding him/her to contact his/her patient and ask her to return for rescreening or refer her to the STD clinic for this purpose, Handsfield explains.

By tracking reported cases, as well as the number of testing requests at local labs, public health officials soon will have ongoing data on the frequency with which infected women return for rescreening, as well as their test results, says Handsfield.

What is the cost of such a program? Not that much, says Handsfield, who offers this thumbnail calculation:

If an STD program performs 5,000 chlamydia tests in women per year and has a 10% positivity rate, then only 500 women are subject to rescreening. If 60% of these patients are retested, this results in 300 "extra" tests per year — a 6% increase in the cost of the testing program, he concludes.

"Remember, too, that most rescreening can be done without a full clinic visit; the patient can just deliver a urine or vaginal swab specimen, so the clinical encounter costs are nil," explains Handsfield. "The remaining costs are just those of the telephone and mailed reminders, [so] in that same program [5,000 tests with 500 positives], the cost is that of a few hundred phone calls and a couple of hundred letters."

Testing, education key

As vital as rescreening efforts are in driving down rates of chlamydia infection, they are just one facet of a multipronged approach in controlling the STD’s infection rates, says Handsfield. Prompt partner treatment and patient education also play key roles.

More frequent screening may be useful, but interventions also are needed to help women reduce their risk of re-exposure to chlamydia, agrees Xu. He and the analysis authors point to evidence that a two-session, 40-minute total interactive, client-centered HIV/STD counseling resulted in an overall reduction in STD incidence of about 30% after six months and 20% after 12 months of follow-up.3 Stratified analysis of that data showed that the relative effectiveness of counseling was greatest for adolescent patients with prior STDs.

Look to the update of the CDC’s Guidelines for Treatment of Sexually Transmitted Diseases to include information on rescreening of women with chlamydial infection, says Handsfield. The publication is due for release this fall, he says.

"I predict that within a couple of years, rescreening will be recognized as a sine qua non of effective chlamydia prevention," states Handsfield. "All reproductive health clinics and providers should rush to initiate routine rescreening of women with chlamydial infection as promptly as possible."


1. Xu F, Schillinger JA, Markowitz LE, et al. Repeat Chlamydia trachomatis infection in women: Analysis through a surveillance case registry in Washington State, 1993-1998. Am J Epidemiol 2000; 152:1,164-1,170.

2. Kamb ML, Fishbein M, Douglas JM, et al. Efficacy of risk-reduction counseling to prevent human immunodeficiency virus and sexually transmitted diseases: A randomized controlled trial. JAMA 1998; 280:1,161-1,167.

3. Centers for Disease Control and Prevention. Chlamydia in the United States. Atlanta; 2001.