RESUMO
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 womwn 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 test between 1 and 4 months of age, or were HIV antibody positive after 18 months. Education regarding infant treatment and use of formula insteadof breast feeding was provided. Results: Between 199 and August, 2000. HIV status was determined for 145 infants. Compliance with intra-partum treatment, infant treatment and use of formula was 88.2 percent. Intra-partum zidovudine treatment was completed in 134/145 (92.6 percent) of patients; 88.1 percent had rupture of membranes < 4 hours; 85.4 percent 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 percent; CI: 0.1 percent - 5.4 percent). The only risk factor significantly associated with transmission was a failure to use zidovudine intra-partum in 2 of the 4 mothers (50 percent versus 6.4 percent 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 levelof compliance for use of anti-retroviral drugs, the provision of health education to mothers, and use of formula for all exposed infants.