Though health experts have long known that chlamydia often afflicts teenage girls, new research conducted at the School of Medicine shows that the infection may be more than a one-time visitor.

The study suggests that recurring chlamydia infections occur in 30 percent of young women between the ages of 14 and 19. That rate is higher than previous studies have indicated, creating new concerns for victims of the most common sexually transmitted disease.

The project examined 411 young women, half of whom were initially diagnosed with chlamydia and 30 percent of whom reported repeat infections over the course of the study. The research was conducted in 10 Connecticut health centers over four years, a time frame that allowed for extensive data collection, said Linda Niccolai, an epidemiology and public health professor who led the project.

“Because we were able to follow the women in this study for a longer period of time … we were able to get the most complete picture possible of their chlamydia history,” Niccolai said. “And this infection is much more common than we thought; over half the girls had at least one episode, and one-third of the sample had repeat infections.”

The study was published in the March edition of the Archives of Pediatrics and Adolescent Medicine.

Chlamydia is a bacterial infection that damages a woman’s reproductive organs and also can cause pelvic inflammatory disease, chronic pelvic pain and infertility. It can usually be treated with a single dose of oral antibiotics.

While the results of the study indicate a rise in repeat chlamydia infections, they do not explain the causes. The researchers speculate that faulty communication between sex partners, general lack of knowledge about sexually transmitted infections and multiple sex partners contribute to the problem to varying degrees.

“This is the next big question to answer, because we really do not know what the biggest contributor is to repeat infections,” Niccolai said. “Certainly all of these factors play a role, but the relative magnitude of each one is unknown, and we are currently doing research to answer precisely this question.”

David Roth, the chief of Obstetrics/Gynecology at Yale University Health Services, said one difficulty with treating chlamydia is that it is not easy to ensure that patients comply with prescribed treatments, such as refraining from sexual activity until both sexual partners are cured of the infection.

Increased testing for sexually transmitted diseases may seem like an obvious solution to higher infection rates, but researchers said they are wary of this option’s viability because men and women do not seek testing with the same frequency.

“Young women are more likely to have contact with the health care system,” Niccolai said. “They are more likely to seek reproductive health care for an annual gynecologic exam or for birth control. [But] men do not regularly seek health care, unless they have a problem.”

Niccolai said the ease with which chlamydia can be treated might encourage some women to be more lax about taking preventative measures, even after their first infection.

“While this is great news for people who are infected, I think the ease with which it can be treated also results in people thinking the infection is ‘no big deal,’ which is a problem for prevention,” Niccolai said. “It is just not seen as very serious.”

Increased sexual health education is another possible solution.

Some, including Roth, stress that institutional initiatives are useful for health education. Others, like Robert Szykowny ’08, co-coordinator of Community Health Educators — a Yale organization that trains Yale students to teach New Haven high school students about health education — stress the importance of communication between sexual partners and early education.

“In terms of preventative measures, it’s about finding new ways to spread the message effectively,” Szykowny said, speaking in his capacity as a student. “It’s about how to get everyone on the same page about this.”

Szykowny added that institutions like YUHS “cannot be responsible for taking on the spread of information” because health education needs to start earlier than one’s college years.

“By the time you’re 18, patterns get set,” Szykowny said. “So the more young people learn about things, the better it is.”

Niccolai said the data in the study were collected through multiple sources, including self-reports, urine-based tests, medical records and health department reports.