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Chlamydia rates continue to rise
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In many areas of the United States, there has been a recent increase in sexually transmitted infection screening and treatment programs. For example, in 2002, the screening rate of 16- to 25-year-old females using commercial insurance or Medicaid was 29.8%; by 2008, this percentage had increased to 44.7%. This has resulted in the detection and treatment of hundreds of thousands of infected young people.
Toni Darville
In 2010, 1,307,893 infections were reported to the CDC, with a peak in prevalence of 6.8% among sexually active females aged 14 to 19 years and highest rates reported in black women. A logical and appropriate response of health care personnel, who are becoming increasingly aware of this infection, is a further increase in screening. It is likely that increased screening and emphasis on case reporting; combined with the enhanced sensitivity of nucleic acid amplification tests; the convenience of testing self-obtained lower vaginal swabs in women; and urine samples from men have all combined to result in a continued rise in the numbers of Chlamydia infections being reported to the CDC.
Cause for decrease of PID
An important question is whether earlier and more frequent detection and treatment of chlamydial infections through screening leads to decreased rates of pelvic inflammatory disease (PID) and the long-term complications of ectopic pregnancy and infertility. Recent studies indicate these programs are having a desired effect. Rates of PID have decreased in the US, British Columbia and the United Kingdom since control programs were initiated. For example, insurance claims data reveal that the rates of PID among privately insured women in the US declined 25.5% from 2001 to 2005 among all age groups examined and within all geographic regions. Rates of ectopic pregnancy determined among commercially insured women in the US between 2002 and 2007 are significantly lower than those reported from 1997 to 2000. Although it is difficult to estimate the proportion of infertility attributable to chlamydial infection, the National Assisted Reproductive Therapy (ART) Surveillance System observed a steady decline from 1999 to 2009 in the rate of ART cycles for infertility among US women. Additionally, married women in the US aged 15 to 44 years who reported 12-month infertility decreased significantly from 1982 to 2002, and again from 2002 to 2008.
Some experts have questioned whether increased screening and earlier treatment have a negative effect on the development of protective immunity. Studies from our lab using the mouse model of chlamydial genital infection indicate early antibiotic treatment can prevent disease without diminishing the adaptive immune response. We recently reported that mice that sustained two infections that were abbreviated by antibiotic treatment developed an adaptive immune response that was effective in significantly reducing bacterial burden upon challenge, and in protection from oviduct disease.
Although human chlamydial infections are less aggressive than those in the mouse model, and likely induce a less robust immune response, these animal data are encouraging. It is possible that although the immune response that develops in females after natural infection is not sufficient to prevent infection at the level of the cervix, it is able to reduce bacterial burden to a level that is less prone to cause irreversible tissue damage. Furthermore, it just makes good clinical sense that earlier detection, treatment and eradication of infection should decrease the rate of complications and decrease spread to sexual partners.
Additional protective measures
Primary care providers need to remember that rates of chlamydial infection are highest in 15- to 19-year-old girls and 20- to 24-year-old men. When these young people present for care for their acne, asthma or any health issue, the visit should be seen as an opportunity to discuss safe sex practices and offer screening to those at risk. Additionally, for health care workers in EDs and clinics, where young people are seeking care for potential STI exposure, clinical interventions that enhance patient notification and partner notification should be implemented.
Too often empiric treatment is given to at-risk adolescent females, and they are never notified of their test results. This prohibits their ability to notify their sex partner and decreases the chance that they will alter their sex practices to safer behaviors. Patient-initiated partner notification greatly enhances STI prevention, but many barriers exist, including the potential that young women are in abusive relationships. Thus, optimum management requires an assessment for intimate partner violence, and support to address fears concerning partner notification.
Screening and counseling teens
Because C. trachomatis is the leading identifiable cause of PID and its complications, a vaccine to prevent chlamydial infections would be of significant benefit. Until such a vaccine is available, it must be remembered that effective antibiotic therapy exists for this prevalent pathogen, and current data indicate that identification of patients with C. trachomatis infection paired with appropriate therapy is effective in decreasing the significant morbidities that can result from PID. Given the continued high prevalence of chlamydial infection in teenagers, and the significant long-term complications that can result from infection in young women, pediatricians and adolescent physicians should take advantage of teen health care visits to provide counseling and offer a screening test.