OBJECTIVES: To determine the HIV vertical transmission rate (VTR) and associated risk factors by use of zidovudine and infant care education in Brazil. METHODS: Since 1995, a prospective cohort of HIV infected pregnant women has been followed at the Federal University of Rio de Janeiro. A multidisciplinary team was established to implement the best available strategy to prevent maternal-infant HIV transmission. Patients with AIDS or low CD4 and high viral load received anti-retroviral drugs in addition to zidovudine. Children were considered infected if they had 2 positive PCR-RNA tests between 1 and 4 months of age, or were HIV antibody positive after 18 months. Education regarding infant treatment and use of formula instead of breast feeding was provided. RESULTS: Between 1995 and August, 2000, HIV status was determined for 145 infants. Compliance with intra-partum treatment, infant treatment and use of formula was 88.2%. Intra-partum zidovudine treatment was completed in 134/145 (92.6%) of patients; 88.1% had rupture of membranes < 4 hours; 85.4% of mothers were asymptomatic. The mean CD4 count was 428.4 cells and mean viral load 39,050 copies. HIV vertical transmission rate was 4/145 (2.75%; CI: 0.1%-5.4%). The only risk factor significantly associated with transmission was a failure to use zidovudine intra-partum in 2 of the 4 mothers (50% versus 6.4% in non-transmitting mothers). A trend toward low CD4 and high viral load at entry, and rupture of membranes > 4 hours were associated with increased HIV transmission. CONCLUSION: HIV vertical transmission in Brazil was reduced to a level similar to other countries with the most effective prevention programs using a multidisciplinary team approach. A high level of compliance for use of anti-retroviral drugs, the provision of health education to mothers, and use of formula for all exposed infants.
Brazil; HIV; prevention; perinatal transmission; zidovudine
