STD Quarterly

Reinfection is common after STD treatment

You have just written a prescription for an adolescent female to treat a chlamydial infection. When you close her file, what are the chances it will reappear in your inbox in the next month or two?

The probability is high. While antibiotic treatment is effective in curing sexually transmitted diseases (STDs), reinfection is common, according to results of a new study.1

To find out how frequently reinfection occurs in the year following treatment, researchers tracked 2,419 men and women who were participating in a large study of HIV prevention counseling. After an initial examination, participants returned every three months over the next year, where they underwent STD testing and were questioned about symptoms and sexual activity since their last visit.

During the study, 26% of the women and 15% men had at least one new STD infection. Many of the participants who developed new infections had no symptoms and were unaware that they were infected again until they were told of the test results.1

It is very important that clinicians stress the need for rescreening following treatment for such infections as chlamydia and gonorrhea because these persons are at high risk for new asymptomatic infections that would go undetected without rescreening, says Thomas Peterman, MD, MSc, an epidemiologist at the Centers for Disease Control and Prevention (CDC). Such asymptomatic infections can lead to infertility and ectopic pregnancy, notes Peterman, lead author of the new research.

Among women infected with a sexually transmitted infection at baseline, 19.6% had a new infection at three months, and reinfection at three months was almost as common in men (16.1%), Peterman reports. While risk of reinfection was greatest at the three-month interval, it remained high at six, nine, and 12 months as well, he says. Two-thirds (66.2%) of these sexually transmitted infections were asymptomatic.

The data suggest that patients — men and women — diagnosed with chlamydia, gonorrhea, and trichomoniasis should be advised to return in three months for rescreening because they are at high risk for a new asymptomatic infection, states Peterman.

"Chlamydia and gonorrhea remain a major threat to reproductive health in the United States," Peterman says. An estimated 2.8 million cases of chlamydia, and more than 700,000 cases of gonorrhea, occur annually in the United States, but many have no symptoms and go undiagnosed, he says. "Both can lead to infertility if left untreated," Peterman says.

The CDC is looking at different strategies to increase return rates for STD testing, but it has not been easy to get people to come back, he notes.

In one recent CDC study, researchers looked at interventions designed to encourage public STD clinic patients infected with chlamydia/gonorrhea to return for rescreening three months after initial treatment.2 Cost data were collected and combined with study data on return rates and positivity rates among returning patients to compare the interventions' cost-effectiveness.

Patients were randomized to one of three intervention arms:

  • In Intervention 1, patients were given a verbal recommendation to return for a chlamydia and gonorrhea screening in three months and given a reminder card with five to seven reasons for returning.
  • In Intervention 2, patients were given a brief verbal recommendation and reminder card, but they also were told they would receive $20 on their return as a form of incentive.
  • In Intervention 3, patients received a verbal recommendation to return and a reminder card, but they also participated in an interview and counseling session to help them assess risks, identify barriers to returning, and identify reasons and motivations for returning. Patients in the third intervention also were given a reminder phone call and mailed a letter three months after the counseling session to encourage their return.

Data indicate that the brief recommendation with a telephone reminder yielded the highest return rate (33%) and was the least costly in terms of cost per infection treated.2 In-depth motivational counseling that helped clients identify risk factors and provided reasons for returning was more costly than a phone reminder alone and was not more effective, researchers found.2

The CDC is working in Washington, DC, New York City, and San Diego to implement rescreening in STD clinics, reports Peterman. People who return for rescreening at these clinics can choose to have a visit that includes only testing — with no exam — so the visit remains brief, states Peterman.

The clinics are mailing reminders to patients to encourage them to return, reports Peterman. Use of telephone call reminders is being considered; however, the clinics are somewhat limited in what they can do in this area due to concerns for confidentiality and limited staff time, he adds.

"I think we need to get to a point where patients understand that an infection means they need to do some things differently in the future, Peterman says. One of those changes is to be rechecked to see if they have a new infection, he explains, "because they are at risk, and infections are often asymptomatic, they won't know about it without a test. It takes a while for behaviors to change, so as clinicians get in the habit of telling patients to return, and then reminding them, their patients will be more likely to return."


  1. Peterman TA, Tian LH, Metcalf CA, et al. High incidence of new sexually transmitted infections in the year following a sexually transmitted infection: A case for rescreening. Ann Intern Med 2006; 145:564-572.
  2. Gift TL, Malotte CK, Ledsky R, et al. A cost-effectiveness analysis of interventions to increase repeat testing in patients treated for gonorrhea or chlamydia at public sexually transmitted disease clinics. Sex Transm Dis 2005; 32:542-549.