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.
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
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.
Dr. Darville is the Carol Ann Craumer Professor of Pediatrics and Chief of Infectious Diseases at Children’s Hospital of Pittsburgh, as well as Professor of Pediatrics and Immunology at the University of Pittsburgh School of Medicine. She is also a member of the Infectious Diseases in Children Editorial Board. Disclosure: Dr. Darville reports no relevant financial disclosures.