Serum level of maternal human immunodeficiency virus (HIV) RNA, infant mortality, and vertical transmission of HIV in Zimbabwe

Maternal human immunodeficiency virus (HIV) RNA load, vertical transmission of subtype C HIV, and infant mortality were examined in 251 HIV-seropositi ve women and their infants in Zimbabwe. Demographic characteristics, health and medical histories, serum HIV RNA loads, and CD4(+) lymphocyte counts f or mothers were examined by logistic regression analysis to determine signi ficant risk factors and their odds ratios for transmission and infant morta lity. Tenfold (1 log(10)) incremental increases in maternal HIV RNA were as sociated with a 1.9-fold increase (95% confidence interval [CI], 1.2-2.9) i n transmission and a 2.1-fold increase (95% CI, 1.3-3.5) in infant mortalit y (P <.01). Maternal CD4 cell counts and demographic and medical characteri stics were not significant predictors of transmission, However, maternal CD 4 cell counts below the median (400/mm(3)) were significantly associated wi th infant mortality (P=.035, Fisher's exact test). The maternal level of se rum HIV is an important determinant of vertical transmission and infant mor tality in subtype C infection In Zimbabwe.