39. American College of Obstetricians and Gynecologists. Prevention of human immune deficiency virus infection and acquired immune deficiency syndrome. Statement of ACOG Committee on Obstetrics: Maternal and Fetal Medicine and Gynecologic Practice. Washington, D.C.: American College of Obstetricians and Gynecologists, 1987.

40. Lewis HE. Acquired immunodeficiency syndrome: state legislative activity. JAMA 1987; 258:2410-4.

Burden of Suffering: An estimated 3-4 million persons acquire chlamydial infections each year in the United States.' This organism is responsible for about half of all cases of nongonococcal urethritis and acute epididymitis in men and about half of the cases of mucopurulent cervicitis in women. It has been estimated that chlamydial infections are responsible for about 25-50% of the 1 million cases of pelvic inflammatory disease (PID) that are reported annually in the United States.2 PID is an important cause of infertility and ectopic pregnancy in American women. About half of the sexual partners of persons with chlamydial infection are also infected with this organism. The economic costs of chlamydial infection are estimated to be over $1 billion per year.2 Chlamydial infection is more common in persons under age 25, especially adolescents.2 Other risk factors for chlamydial infection in asymptomatic persons include having multiple sexual partners, a new sexual partner in the preceding two months, and a sexual partner with a chlamydial infection.2

storage and transport requirements. These include two methods for direct antigen testing (fluorescent antibody microscopy and enzyme-linked immunoassay) and serologic testing. Each test has important disadvantages, however, that currently limit its use as a routine screening test.212 Fluorescent antibody microscopy has comparable sensitivity and specificity to chlamydial culture, but it is a labor-intensive procedure requiring special laboratory equipment and skilled technicians in order to produce reliable results. Enzyme-linked immunoassay (ELISA) does not require specially trained personnel and utilizes instruments that can produce standardized results in large volume, but its sensitivity and specificity for chlamydial infection are uncertain. Both tests, however, may be useful in areas where culture is not available or too costly. Serologic testing remains primarily a research tool due to difficulties associated with performing the laboratory procedure. Chlamydial cytology, once the only available test for detecting chlamydial infection, has been shown to be an insensitive screening test, except when evaluating newborn conjunctival scrapings, for which the sensitivity is 95% compared with culture.2

Effectiveness of Early Detection: Early detection of chlamydial infections in asymptomatic persons permits initiation of antibiotic therapy and prevention of complications. There have been few controlled studies examining whether early detection and treatment of asymptomatic persons result in improved outcome. It is thought, however, that occult infections, which may result in serious complications, account for a large proportion of chlamydial infections (up to 80% in women and 10-20% in men).2 Over 95% of such infections can be cured with a seven-day course of an appropriate antibiotic.2 Treatment failures are usually due to failure to treat sexual partners, noncompliance with therapy, reinfection, or laboratory error. There is also evidence that chlamydia screening of pregnant women and treatment of positives with erythromycin can reduce the incidence of neonatal infections,13,14 but a randomized controlled trial is needed to provide conclusive evidence of efficacy.

It is not known whether the yield of screening and the benefits of reduced morbidity are of sufficient magnitude to justify their considerable costs. In a recent study, the charge per test was $25 for culture and $12 for direct antigen testing.10 Several centers have attempted to examine the cost-effectiveness of screening for chlamydia under various conditions. They have found that routine testing is cost-effective for women attending clinics for sexually transmitted diseases who do not receive empirical antichlamydial therapy or at routine gynecologic visits if the prevalence of chlamydia in the patient population exceeds 7%.1 Another study concluded that screening was cost-effective if the prevalence was 8% and if only direct antigen testing was used.10 Others have disagreed with the assumptions used in such studies and have suggested that screening is appropriate in settings with lower prevalence.16,17

15

Recommendations of Others: The Centers for Disease Control (CDC) recommends chlamydial testing in asymptomatic persons who attend clinics for sexually transmitted diseases and who otherwise would not receive antichlamydial treatment; attenders of other high-risk health care facilities (e.g., adolescent and family planning clinics); and persons in urban settings who otherwise would not be offered chlamydial treatment and who are younger, of low socioeconomic status, or have multiple sexual partners.2 The CDC also recommends chlamydia screening at the first prenatal visit of pregnant women who are less than 20 years of age, unmarried, have multiple sexual partners, or have a history of another sexually transmitted disease.2 The Canadian Task Force also recommends screening high-risk groups and pregnant women. The American College of Obstetricians and Gynecologists recommends chlamydial culture at the first prenatal visit and during the third trimester in pregnant women at increased risk (e.g., those who are single, less than 20 years old, reside in a socially disadvantaged community [e.g., inner city], have other sexually transmitted diseases, or begin prenatal care late).19

The CDC2 and the American Academy of Pediatrics20 recommend instilling erythromycin ophthalmic ointment, tetracycline ointment, or silver nitrate into the eyes of newborns as soon as possible after birth to prevent both gonococcal and chlamydial ophthalmia neonatorum.

Discussion: The efficacy of antibiotic therapy for maternal chlamydial infection in preventing neonatal complications requires further study, but there is

Clinical Intervention: Routine testing for Chlamydia trachomatis is recommended for asymptomatic persons who attend clinics for sexually transmitted diseases, diseases, attend other high-risk health care facilities (e.g., adolescent and family planning clinics), or have other risk factors for chlamydial infection (e.g., age less than 20, multiple sexual partners, or a sexual partner with multiple sexual contacts). The optimal frequency of such testing has not been determined and is left to clinical discretion. Recent sexual partners of persons with positive cultures also require testing and treatment. Pregnant women in the high-risk categories listed above should be tested for chlamydia at the first prenatal visit. Erythromycin 0.5% ophthalmic ointment or tetracycline 1% ophthalmic ointment should be applied topically to the eyes of all newborns as soon as possible after birth and no later than 1 hour of age.

Note: See Appendix A for the U.S. Preventive Services Task Force Table of Ratings for this topic. See also the relevant Task Force background paper: Horsburgh CR, Douglas JM, LaForce FM. Preventive strategies in sexually transmitted diseases for the primary care physician. JAMA 1987; 258:814-21.

References

1. National Institutes of Health. NIAID Study Group on Sexually Transmitted Diseases: 1980 status report. Summaries and panel recommendations. Washington, D.C.: Government Printing Office, 1981: 215-64.

2. Centers for Disease Control. Chlamydia trachomatis infections: policy guidelines for prevention and control. MMWR [Suppl 3] 1985;

34.

3. Thompson SE, Washington AE. Epidemiology of sexually transmitted Chlamydia trachomatis infections. Epidemiol Rev 1983; 5:96123.

4. Nettleman MD, Jones RB, Roberts SD, et al. Cost-effectiveness of serology and cell culture for Chlamydia trachomatis: a study in a clinic for sexually transmitted diseases. Ann Intern Med 1986; 105:18996.

5. Jones RB, Katz BP, Van Der Pol B, et al. Effect of blind passage and multiple sampling on recovery of Chalmydia trachomatis from urogenital specimens. J Clin Microbiol 1986; 24:1029-33.

Burden of Suffering: Primary episodes of genital herpes occur each year in approximately 200,000 to 500,000 Americans,' and as many as 20 million persons are already infected. The chief morbidity associated with infection with the herpes simplex viruses (HSV-1 or HSV-2) are painful vesicular and ulcerative lesions that erupt in the anogenital and oral-facial areas.3 About 4% of symptomatic primary episodes require hospitalization.* In most cases the virus establishes latent infections in spinal cord ganglia, and over a period of years the patient may experience periodic episodes of herpetic eruptions. Sexual contacts of persons with active and inactive disease are at risk of becoming infected. Pregnant women with genital herpes infection can transmit the infection to the newborn during vaginal delivery. An estimated 400 to 1000 cases of neonatal herpes occur each year in the United States." Neonates have the highest frequency of visceral and central nervous system infection of any HSV-infected patient population. If untreated, death occurs in 65% of infants; less than 10% of survivors with central nervous system infection have normal development.3 Genital herpes costs the United States an estimated $500 million per year.°

Efficacy of Screening Tests: The sensitivity of all tests for herpes simplex depends primarily on the stage of the lesion at the time of testing and whether the patient is experiencing a primary or recurrent episode.3 The principal test for detecting herpes simplex, viral culture, has excellent sensitivity (95%) during primary episodes and moderate sensitivity (65%) during recurrent episodes, but its sensitivity and specificity when performed on asymptomatic persons is uncertain. In addition, viral culture is expensive, not universally available, and results are often available only after two to four days. More rapid diagnostic methods, such as cytology (Papanicolaou or Tzanck smear), immunoperoxidase tests, immunofluorescence, and enzyme immunoassay, have been proposed for screening, but they appear to be less sensitive than viral culture.'

Since an estimated 70-80% of infants with neonatal herpes are born to women with no history or physical findings of genital herpes at the time of delivery,9 screening asymptomatic pregnant women has the potential of identifying undetected carriers

Routine

and preventing neonatal transmission. screening of pregnant women is likely to have low yield, however; even in women with a history of genital herpes predating the pregnancy, HSV can be isolated during asymptomatic intervals in only 1% of cultures.10 In addition, a positive test result in an asymptomatic woman may be of limited value in predicting the risk of transmission during delivery, especially if active lesions are not present during labor." Even for infants of mothers with a history of recurrent infection who are exposed to HSV at the time of delivery, the risk of infection is thought to be less than 10%.12

3,13

Effectiveness of Early Detection: The isolation of herpes virus in asymptomatic nonpregnant persons is of limited value. There is no effective treatment for eradicating latent herpes infections or completely preventing recurrences. Oral acyclovir reduces the duration of painful episodes, viral shedding, and systemic symptoms in primary herpes infection; 13 it may also help prevent recurrent episodes in patients with very frequent or severe recurrent genital herpes.1 Little information is available, however, on its effect on asymptomatic viral shedding. Further data are also needed on the long-term toxicity of this agent, the frequency with which resistant strains emerge, and the effects of long-term therapy on transmission."

Early detection of herpes is of greater importance during pregnancy, however, because cesarean section can be performed to prevent transmission of the virus to the newborn. This has been shown to result in lower mortality. In one study, weekly cultures beginning at the 36th week were performed on 57 pregnant women with culture-verified HSV infection; cesarean section was performed if the culture preceding the onset of labor was positive or the disease became reactivated.15 The investigators found very low neonatal mortality, with 58 of the 60 newborns surviving. This and similar studies, however, have lacked controls and randomization.

More definitive prospective studies are needed to determine the proper indications for operative delivery, especially when the risk of HSV transmission during delivery is reduced (e.g., in women without laboratory or clinical evidence of active disease in