7,000 perinatally acquired AIDS cases were recorded nationwide, the vast majority of which were among African-American and Hispanic children. The distribution of perinatally acquired AIDS is highly concentrated, with three-quarters of cases diagnosed in eight states/jurisdictions: New York, Florida, New Jersey, California, Puerto Rico, Texas, Maryland, and Pennsylvania. Many states have very low prevalence: 23 states account for a total of less than 2% of reported perinatal AIDS cases.
The number of pediatric, perinatally acquired AIDS cases rose rapidly in the late 1980s and early 1990s, peaked around 1992, and subsequently declined 43% by 1996. According to the CDC, this dramatic decline, coupled with other recent trend data, point to the conclusion that preventive efforts in this country have been successful in reducing perinatal AIDS transmission.
Trends by age at diagnosis show that the largest declines are among children diagnosed as infants, with substantial declines also among children diagnosed at ages one to five years. However, for older children, similar levels of decline have not been observed. These findings are consistent with the expectation that efforts to prevent perinatal transmission would be reflected earliest in infants because older children were born before ACTG 076 (AIDS Clinical Trials Group protocol number 76).
PCP (Pneumocystis carinii pneumonia) is the most common AIDS-defining condition in children, occurring most prominently in infancy. Since recommendations regarding PCP prophylaxis were evolving during the same period that dramatic declines occurred in perinatally acquired pediatric AIDS cases, it is useful to look at whether declines in pediatric AIDS reflect more than declines in PCP. CDC surveillance findings show substantial declines in AIDS among infants—not only in those with PCP as the presenting diagnosis, but also in those with other opportunistic infections. This indicates that the decline in pediatric AIDS cases is not being driven solely by changes in PCP, but rather appears to reflect declining perinatal transmission rates.
In order to estimate the impact of the ACTG 076 results, Byers and colleagues (1998) compared two sets of estimates of children born with HIV infection and children diagnosed with AIDS by year through 1997. The first series is based on extrapolating data through 1994 from the SCBW, and assumes a gradual decline in the number of HIV-infected women giving birth. These "SCBW" estimates, however, assume a constant transmission rate of 21.43%, representing, as a base case, the effect of no progress in preventing transmission. The second series of estimates is based on the number of children reported with AIDS, adjusted for incubation time and reporting delays. This "surveillance" series, therefore, estimates the number of children born with HIV infection or diagnosed with AIDS that could eventually be observed. The surveillance and SCBW estimates are similar through 1990, but taken together indicate a 42% decrease in the number of HIV-infected births in 1995 and a 65% decrease in 1997. In terms of AIDS diagnoses, the estimates suggest a 16% decrease in 1995 and a 29% decrease