Vertical transmission of HIV-1: lack of detectable virus in peripheral blood cells of infected children at birth

Abstract

Objective: To evaluate the time-course of HIV-1 detection in peripheral blood mononuclear cells (PBMC) from newborns at risk of vertically acquired infection.

Design and method: Forty-six infants born to HIV-1-infected mothers were enrolled at birth and examined virologically and clinically in the perinatal period and every 30 days for the first 3 months of life. Follow-up was conducted at intervals of 2-3 months. HIV-1 detection in PBMC was performed using virus culture and polymerase chain reaction (PCR) assay.

Results: Only one out of 24 newborns tested within 48 h of delivery and two out of 22 infants tested between 3 and 15 days of age were found to be HIV-1-positive by both PCR and virus culture. Further testing performed between 30 and 60 days of life identified an additional eight HIV-1-positive children. Subsequent viral, immunological and clinical follow-up confirmed PCR and virus culture results obtained in 30-60-day-old children.

Conclusions: Infected infants had detectable levels of HIV-1 in their PBMC at 1 month of age. The negative PCR and virus culture findings in PBMC of newborns indicate strongly that HIV-1 cannot be diagnosed at birth in the majority of cases, and suggests that viral transmission could occur during late pregnancy and/or delivery.