High Prevalence of Asymptomatic CMV Shedding in Healthy Children Attending the Minnesota State Fair

Background: Young children in the household are a known risk factor for maternal CMV infection and consequently, congenital infection in infants. However, little is known about viral shedding in pre-school aged children.

Objectives: To estimate the prevalence of CMV DNA shedding and CMV antibodies among healthy children and their mothers.

Study Design: A study of children ages 0 through 5 years was undertaken at the 2019 Minnesota State Fair. Children and their mothers were assessed for CMV shedding by procurement of a saliva swab for CMV PCR testing. An optional finger-stick for capillary blood was used to assess CMV antibodies.

Results: A total of 109 children and 85 mothers were enrolled. The prevalence of CMV saliva shedding among children (mean age 3.1 years, SE=0.16) and their mothers was 12/109 (11.0%) and 1/85 (1.2%), respectively. The prevalence of CMV DNA among children peaked at 3 years of age (26%) while the mean viral load was greatest at one year of age (236,693 IU/mL). CMV IgG antibodies among those who agreed to a finger-stick were detected in 16/35 mothers (45.7%) and 0/7 children (0%). Mothers of children aged 5 years or greater had the highest seroprevalence (61.5%).

Conclusions: The prevalence of CMV salivary shedding in this unselected sample of young children was approximately 11.0%. The overall maternal seroprevalence in our sample was <50%, suggesting these women are at risk for acquisition of a primary CMV infection in subsequent pregnancies.