Lack of evidence of vertical transmission of human immunodeficiency virus type 2 in a sample of the general population in Bissau.

Twenty-nine human immunodeficiency virus type 2 (HIV-2) seropositive women identified in a cross-sectional study in Bissau in 1987 participated in a follow-up study in 1988, where each was matched for age and marital status with two HIV-2 seronegative women. Detailed information about all pregnancies was obtained. The HIV-2 seropositive women and their controls had similar mean numbers of pregnancies, live children, children who died, and abortions. The HIV-2 seropositive women did not have a greater risk of having had an abortion or a child who died than did the HIV-2 seronegative women. No difference in survival was seen between children born to HIV-2 seropositive and HIV-2 seronegative women. The H/S-ratios and CD4 numbers were lower in the seropositive group, but none had values lower than 0.4 and 0.4 x 10(9)/L, respectively. Seven prospectively observed children born to HIV-2 seropositive mothers showed no sign of infection. The lack of evidence of transmission of HIV-2 from mother to child is suggested to be due to the absence of marked immunodeficiency in this random sample of the general population.