Antiretroviral therapy has been shown to reduce rates of congenital CMV infection. Little information is available on the possible impact of antiretroviral therapy on postnatal breastfeeding-associated CMV infection acquisition. A cohort of 89 HIV-infected mothers and their children was studied. Women received antiretroviral therapy from week 25 of gestation until 6 months postpartum or indefinitely if meeting the criteria for treatment. All women were evaluated for CMV IgG presence and CMV DNA in breast milk. Children were tested for CMV infection by either the presence of IgM or the presence of CMV DNA in plasma at 1, 6 and 12 months and by the presence of IgG at 24 months. All mothers had high titers of CMV DNA in breast milk (5.7 log at Month 1 and 5.1 log at Month 6). Cumulative CMV infection rates were 60.3 % at Month 6, 69 % at Month 12 and 96.4 % at Month 24. There was a significant negative correlation between the duration of antiretroviral treatment during pregnancy and levels of CMV DNA in breast milk at Month 1 (P = 0.033). There was a trend for a correlation between high titers of CMV DNA in breast milk at 6 months and CMV infection at 6 months (P = 0.069). In this cohort, more than 95 % of the children had acquired CMV infection by 2 years of age. Besides breastfeeding, which played a major role, also horizontal transmission between 1 and 2 years was certainly relevant in determining CMV infection acquisition.
Keywords: Breastfeeding; Cytomegalovirus; HIV; Infant; Vertical transmission.