Seroprevalence of varicella-zoster virus infection in children from Cochabamba: tropical or temperate pattern?

Objectives: To determine the seroprevalence of varicella-zoster viral (VZV) infections in schoolchildren from the Cochabamba region (Bolivia), and its association with socio-demographic variables, socio-economic status and geographical location.

Methods: Seroepidemiological survey (n = 436) on VZV of schoolchildren living in the Cochabamba region of Bolivia in 2010. An ELISA test was used to measure varicella antibodies. Parents or guardians completed a questionnaire regarding socio-demographic information (age, gender, living area, parental educational level, presence of siblings and number of family members in the household), and a blood sample was collected from each child to check for VZV antibodies. A descriptive and bivariate analysis was performed.

Results: The global prevalence of VZV was 78.2% (95% CI 74.3-82.1). It was higher in females (82.1%), pre-adolescents (aged 10.1-13 years: 81.4%) and adolescents (aged >13 years: 80.2%), in children with less well-educated parents (81.3% to 81.6%), in warmer municipalities (81.4% to 82.2%), in rural areas (80.0%), in children with siblings (80.1%), those who although the latter association was not statistically significant.

Conclusions: The prevalence of VZV infection in childhood was relatively high for a tropical country, and much closer to that of temperate countries prior to the introduction of varicella vaccine into vaccination programmes.