[Vertical transmission rate of the immunodeficiency virus: determinant factors and comparison of results]

Although all newborns to HIV-seropositive mothers have IgG anti-HIV antibodies, since these antibodies cross the placental barrier, only a small proportion of these children are actually infected with the virus. The main objective of this study consisted in estimating the vertical transmission rate of HIV in our environment. A prospective review was conducted of 236 children with HIV infection risk as they were born to HIV seropositive mothers. To calculate the mother-to child transmission we selected only 121 children controlled from birth and for a minimal time of 18 months at Hospital Infantil La Fe. Twenty-one out of these definitely classified 121 children were infected, representing a rate of 16.5%, similar to the rate reported in other European studies. By means of the stratified analysis some factors related to an increased transmission risk for HIV from mother to child were investigated. The possible causes that can explain the variability in the calculated rates for the different groups of investigation since the first pediatric AIDS case was detected are also discussed.