special populations, touched upon throughout this summary, are the homeless and IDUs.
Adolescents are a critical, yet underrecognized, population for the prevention of perinatal HIV transmission. Although the nationwide seroprevalence of HIV infection among adolescents appears to be relatively low, urban areas are disproportionately affected: New York, for example, is estimated to have 20% of the nation's adolescents with AIDS. An estimated 25% of HIV-infected adults nationwide acquired their infection as adolescents (Rosenberg et al., 1994). Adolescents infected with HIV pose unique problems in identification, consent to testing, and entry into care. Traditional HIV "risk assessment" by health care providers misses a significant percentage of cases. There is also a lack of ready access to systems of care by the most disenfranchised adolescents who are most vulnerable to HIV. Consequently, many teenagers are unaware of their HIV infection, having neither been recommended for, nor received, testing. And an HIV-positive test does not ensure access to care. All of these problems may be compounded in pregnancy because of the added social stigma against adolescent pregnancy.
A comprehensive treatment program for adolescents in the Bronx visited by the IOM, the Adolescent AIDS Program of Montefiore Medical Center, has been successful at reducing perinatal transmission of HIV in adolescents. At any given time about one-third of the adolescents in this referral program are pregnant, and virtually all accept antiretroviral therapy. Of 12 babies born to HIV-positive adolescents in 1997, 11 were HIV-negative. The one baby who did test positive was born to a mother in the late stages of AIDS who was non-compliant with the ZDV treatment. The program attributes its success to these features: labor-intensive outreach to adolescents and health care professionals to encourage testing with linkage to treatment; lack of financial barriers to testing and treatment through sliding fee scales and help with obtaining Medicaid and other public financing programs; accessibility through subsidized transportation to the program; a "one-stop shopping" approach enabling teenagers to receive counseling, testing, treatment, and medications for HIV at the same site—both during and after pregnancy (although obstetrical services are available through referral); and understanding the special needs and fears of adolescents.
Among the barriers to HIV testing of pregnant adolescents are physicians' discomfort with discussing sexuality; physicians' lack of awareness that consent to testing (in New York and many other states) can be given solely by the adolescent and need not require the parent; and adolescents' fears of being reported, despite assurances of confidentiality. Among the barriers to acceptance of, and compliance with, treatment are the lack of linkages between testing and treatment programs; adolescents' perception of invincibility and difficulty in