Design
Prospective, longitudinal study lasting 3 years. The PCR tests were performed with coded peripheral blood mononuclear cell lysates, and results were compared with findings using Centers for Disease Control and Prevention (CDC) (Atlanta, Ga) criteria defining HIV infection in children.

Setting
Hospitals, particularly a pediatric hospital in Washington, DC.

Patients
Newborns, young infants, and HIV-infected mothers.

Outcome Measure
Presence or absence of pediatric HIV infection using CDC criteria compared with a diagnosis based on the detected presence or absence of HIV proviral DNA using PCR testing.

Results
One or more blood samples obtained by 62 days of age from 30 (94%) of 32 HIV-infected infants were positive for HIV by routine PCR testing. Blood samples from 32 infants now confirmed to be uninfected tested negative for HIV. Human immunodeficiency virus DNA was detected in blood samples obtained within 48 hours of birth from eight of nine infected infants. In six of these newborns as well as most older infants, HIV DNA was present in such quantity that it was detectable in specimens equivalent to 0.01 mL or less of the original blood sample.

Conclusions
Our PCR procedure can reliably detect the presence or absence of HIV infection during the first 2 months of life. The frequent presence and not uncommon high titer of HIV DNA within 48 hours of birth suggest that much of the transmission of HIV from mother to infant occurs well before birth.

(Arch Pediatr Adolesc Med. 1994;148:250-254)