Purpose of the Study
Pediatrics AIDS Clinical Trials Group Protocol 076 (ACTG 076) documented a reduction in the rate of perinatal transmission of human immunodeficiency virus (HIV) from >25% to 8.3% with a regimen of zidovudine (“AZT”) given antepartum, intrapartum, and to the newborn. The purpose of this study was to examine the effects of abbreviated AZT regimens on HIV transmission.
Data was obtained from the HIV polymerase chain reaction (PCR) Testing Service of the New York State Department of Health. Pregnant women who received abbreviated regimens rather than the recommended regimen did so because of limited prenatal care, or by choice. The requisition form used by the PCR Testing Service included information on the demographic characteristics of the infants and the timing of any perinatal treatment with AZT.
Specimens from 939 HIV-exposed infants were submitted for PCR testing. When treatment was begun in the prenatal period, the rate of HIV transmission was 6.1%; when begun intrapartum, the rate was 10.0%; when begun within the first 48 hours of the infant's life, the rate was 9.3%; and when begun on day 3 of life or later, the rate was 18.4%; in the absence of zidovudine prophylaxis the rate of HIV transmission was 26.6%.
These results confirm the efficacy of AZT prophylaxis and strongly suggests that there are reductions in the rate of perinatal transmission of HIV even with abbreviated regimens that are begun intrapartum, or in the first 48 hours of life.
In the United States, perinatal transmission of HIV is becoming a rare event in situations where effective antiretroviral therapy is initiated in the perinatal time frame. For most of the developing world; however, the intense regimen dictated by ACTG 076 is unaffordable and impractical. This study strongly indicates that abbreviated regimens are still substantially effective in reducing the rate of transmission from mother to infant, and that such abbreviated regimens are effective, although optimal cost benefit analysis will be difficult to conduct.