Prospective Characterization of the Risk Factors for Transmission and Symptoms of Primary Human Herpesvirus Infections Among Ugandan Infants.

Background: Human herpesvirus (HHV) infections are common during infancy. Primary infections are frequently asymptomatic and best studied prospectively by using direct viral detection.

Methods: Oropharyngeal swab specimens were collected weekly from Ugandan newborn infants, their mothers, and other children in the household. Blood specimens were collected every 4 months. Samples were tested for herpes simplex virus (HSV) types 1 and 2, Epstein-Barr virus (EBV), cytomegalovirus (CMV), HHV-6A, HHV-6B, and HHV-8, using quantitative polymerase chain reaction.

Results: Thirty-two infants, 32 mothers, and 49 other household children were followed for a median of 57 weeks. Seventeen mothers had human immunodeficiency virus type 1 (HIV) infection; no infants acquired HIV-1. The 12-month incidence of postnatal infection was 76% for HHV-6B, 59% for CMV, 47% for EBV, 8% for HSV-1, and 0% for HHV-8. The quantity of oropharyngeal shedding by contacts was associated with HHV-6A or HHV-6B transmission. Maternal HIV-1 infection was associated with EBV transmission, while breastfeeding and younger child contacts were associated with CMV transmission. Except for HSV-1, primary HHV infections were subclinical.

Conclusions: By capturing exposures and acquisition events, we found that the incidence and risk factors of infection vary by HHV type. HSV-1 infection, unlike other HHV infections, caused acute clinical illness in these infants.