Some Facts about Chlamydia

SOME FACTS ABOUT CHLAMYDIA

What is Chlamydia?

Chlamydia is a sexually transmitted disease (STD) that is caused by the bacterium Chlamydia trachomatis. Because approximately 75% of women and 50% of men have no symptoms, most people infected with chlamydia are not aware of their infections and therefore may not seek health care.

When diagnosed, chlamydia can be easily treated and cured. Untreated, chlamydia can cause severe, costly reproductive and other health problems which include both short- and long-term consequences, including pelvic inflammatory disease (PID), which is the critical link to infertility, and potentially fatal tubal pregnancy.

Up to 40% of women with untreated chlamydia will develop PID. Undiagnosed PID caused by chlamydia is common. Of those with PID, 20% will become infertile; 18% will experience debilitating, chronic pelvic pain; and 9% will have a life-threatening tubal pregnancy. Tubal pregnancy is the leading cause of first-trimester, pregnancy-related deaths in American women.

Chlamydia may also result in adverse outcomes of pregnancy, including neonatal conjunctivitis and pneumonia. In addition, recent research has shown that women infected with chlamydia have a 3 - 5 fold increased risk of acquiring HIV, if exposed.

Chlamydia is also common among young men, who are seldom offered screening. Untreated chlamydia in men typically causes urethral infection, but may also result in complications such as swollen and tender testicles.

What is the magnitude of the problem?

Chlamydia is the most frequently reported infectious disease in the United States. Though 526,653 cases were reported in 1997, an estimated 3 million cases occur annually. Severe under reporting is largely a result of substantial numbers of asymptomatic persons whose infections are not identified because screening is not available. Highlights of reported data are as follows:

From 1984 through 1997, reported rates⁽¹⁾ of chlamydia increased from 3.2 to 207.0 cases per 100,000 population. This trend primarily reflects increased screening, recognition of asymptomatic infection (mainly in women), and improved reporting capacity rather than a true increase in disease incidence.

In 1997, the reported rate of chlamydia for women (335.8) substantially exceeded the rate for men (70.4), due mainly to increased detection of asymptomatic infection in women through screening. Low rates of reported chlamydia among men suggest that many of the partners of women with chlamydia are not screened or treated.

As in previous years, 1997 rates of chlamydia were highest in the West and the Midwest, where substantial resources have been committed for organized screening programs.

How are adolescents and young women affected?

As many as 1 in 10 adolescent girls tested for chlamydia is infected.

Based on reports to CDC provided by states that collect age-specific data, teenage girls have the highest rates of chlamydial infection. In these states, 15- to 19-year-old girls represent 46% of infections and 20- to 24-year-old women represent another 33%. These high percentages are consistent with high rates of other STDs among teenagers.

Among women entering the Job Corps in 1997, chlamydia rates ranged from 4 - 14% by state (20,000 entrants are screened annually). Chlamydial infection is widespread geographically and highly prevalent among these economically disadvantaged young women between 16 and 24 years old.

What does chlamydia cost?

The annual cost of chlamydia and its consequences in the United States is more than $2 billion. The CDC estimates screening and treatment programs can be conducted at an annual cost of $175 million. Every dollar spent on screening and treatment saves $12 in complications that result from untreated chlamydia.

What is being done to address the problem?

In 1993, Congress appropriated funds to begin a national STD-related infertility prevention program. Through a cooperative effort between CDC and the Office of Population Affairs, the program involves strong collaboration among family planning, STD and primary health care programs, and public health laboratories. Significant progress has been made where screening programs have been fully implemented.

A 65% decline in infection was demonstrated in family planning clinics in Federal Region X (Alaska, Idaho, Oregon, and Washington) in the first 8 years of screening, from 1988 to 1995. These declines have occurred across all age groups since testing began in 1988, although adolescents continue to have the highest rates of disease.

A 31% decline in infection was indicated for females under age 20 during the first 2-1/2 years of initial large-scale screening in Region III (Delaware, the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia), from 7.8% in 1994 to 5.4% during January-June 1996.

A 16% decline in infection was indicated for females under age 20 during the first 2-1/2 years of initial large-scale screening in Region VIII (Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming), from 5.5% in 1994 to 4.6% during January-June 1996.

Strong evidence is now available that chlamydia screening and treatment not only reduces the prevalence of lower genital tract infection, but also decreases the incidence of costly complications, such as PID. A randomized trial of chlamydia screening and treatment in a health maintenance organization demonstrated a 56% reduction in the incidence of PID in the screened group in the 12 months following the trial.

Due to resource constraints, the program continues only as demonstration projects in most parts of the country. CDC estimates that nearly 75% of women at risk reside in 30 states that are only just beginning to screen for chlamydia. For example, in California, Florida, Georgia, Illinois, New York, and Texas, more than 200,000 women in each state who attend publicly funded family planning and STD clinics currently do not have access to screening and treatment.

Since these programs have focused on prevention efforts in women, many men with chlamydia are not diagnosed and treated, thus continuing the cycle of infection.

CDC has developed recommendations for the prevention and management of chlamydia for all providers of health care. These recommendations call for screening of all sexually active females under 20 years of age at least annually, and annual screening of women ages 20 and older with one or more risk factors for chlamydia (i.e., new or multiple sex partners and lack of barrier contraception). All women with infection of the cervix and all pregnant women should be tested.

What still needs to be done?

Programs to provide testing for infection through screening and subsequent treatment are needed nationwide. A successful program must include comprehensive screening and treatment not only for women but also for men. Recent research advances have made available extremely accurate urine tests which make testing of males more feasible and less uncomfortable than older tests. In addition, single-dose antibiotic therapy promises to substantially enhance the likelihood of successful treatment -- especially in adolescents -- as compared to commonly used 7-day oral medication.

1. Rates are per 100,000 population.