AIDS each year (Figure A.3). One of the greatest successes in HIV prevention occurred with the 1994 finding that administration of the antiretroviral drug zidovudine during pregnancy and childbirth could reduce the chances of perinatal transmission by two-thirds (Connor et al., 1994). The rapid implementation and use of zidovudine and other antiretroviral drugs in clinical settings, combined with efforts to identify and treat HIV-infected pregnant women through HIV screening in prenatal care settings, led to dramatic declines in the number of pediatric AIDS cases (Figure A.3). Between 1993 and 1999, the number of pediatric AIDS cases declined by 75 percent (CDC, 2000b).
The demographic populations affected by the epidemic have evolved over time. During the 1990s, women, youth, and racial and ethnic minorities accounted for a growing proportion of new AIDS cases. Geographic distributions have also shifted, with a growing proportion of cases emerging in rural and smaller urban areas.
The increases in AIDS cases among women is consistent with the increase of cases linked to heterosexual transmission. The proportion of annual new AIDS cases among women tripled, from 7 percent to 23 per-