A prospective study of infants born to women seropositive for human immunodeficiency virus type 1. HIV Infection in Newborns French Collaborative Study Group.

Assessment of the risks of transmission of infection with human immunodeficiency virus type 1 (HIV-1) from mother to newborn is difficult, partly because of the persistence for up to a year of maternal antibodies transmitted passively to the infant. To determine the frequency of perinatal transmission of HIV infection, we studied from birth 308 infants born to seropositive women, 62 percent of whom were intravenous drug abusers. Of 117 infants evaluated 18 months after birth, 32 (27 percent) were seropositive for HIV or had died of the acquired immunodeficiency syndrome (AIDS) (n = 6); of the 32, only 2 remained asymptomatic. Another 76 infants (65 percent) were seronegative and free of symptoms, whereas 9 (8 percent) were seronegative but had symptoms suggestive of HIV-1 infection. The infants infected with HIV-1 did not differ from the others at birth with respect to weight, height, head circumference, or rate of malformations, but as compared with newborns who were seronegative at 18 months, their serum IgM levels were higher (78 +/- 81 mg per deciliter vs. 38 +/- 39 mg per deciliter; P less than 0.03) and their CD4 lymphocyte counts were lower (2054 +/- 1221 per cubic millimeter vs. 2901 +/- 1195 per cubic millimeter; P less than 0.006). Neither maternal risk factors nor the route of delivery was a predictor of seropositivity at 18 months; however, 5 of the 6 infants who were breast-fed became seropositive, as compared with 25 of 99 who were not (P less than 0.01). We conclude that approximately one third of the infants born to seropositive mothers will have evidence of HIV-1 infection or of AIDS by the age of 18 months, and that about one fifth of this group will have died.