Seroprevalence of varicella zoster virus in Colombia: A community-based mixture models study

Objectives

To describe the distribution of immunoglobulin (Ig) G antibodies against varicella by sociodemographic characteristics during the period before vaccination in Medellín, Antioquia, Colombia.

Methods

A population seroprevalence based on a previous study carried out in men and women aged 6-64 years, residing in the urban and rural zone of Medellín, Antioquia, Colombia in 2009. A probability sample of 2124 individuals was selected using a multistage sampling design. IgG antibodies against varicella zoster virus were determined in human serum/plasma by an enzyme-linked immunosorbent assay test. Global seroprevalence levels were calculated, considering a sample expansion factor, allowing inference to the population. Antibody distribution was explored worldwide by sex and zone of residence, using finite mixture models.

Results

Global seropositivity was 85.9% (95% confidence interval [CI]: 82.9-88.5) using the manufacturer’s cutoff and 81.5% (95% CI: 78.0-88.5) using the complete data from antibody distribution. Significant seronegativity was detected in the group from 6 to 17 years of age of 20.6% (95% CI: 14.8-27.9), without differences by sex and zone of residence.

Conclusions

The seronegativity in the 6-17 age group shows the need to periodically monitor antibody prevalence in children and young people to guide new vaccination and transmission prevention strategies.