Analysis of factors associated with varicella-zoster virus susceptibility among children 0-12 years old in Taiwan

Abstract

Objectives: Varicella is a highly infectious disease caused by varicella-zoster virus (VZV). The aim of this study was to explore the geographical difference of VZV antibody seroprevalence among children in private vaccination areas in Taiwan, controlling for potential factors relating to varicella susceptibility.

Patients and method: A cross-sectional survey of the seroprevalence of VZV antibodies among children 0-12 years of age was conducted in Taiwan between August and December 2003. Sera of children visiting the outpatient unit of the participating hospitals around the island were collected. Six hundred and fifty-six parents among those of the 931 children studied agreed to answer the self-administered questionnaire regarding the possible factors associated with varicella susceptibility. IgG antibodies to VZV were measured using an enzyme-linked immunosorbent assay kit, Enzygnost anti VZV/IgG.

Results: The susceptibility was the highest at age 1 year, and then decreased as the age increased. Children living in southern and eastern Taiwan showed higher susceptibility to varicella than those living in northern area (odds ratio (OR) = 2.71 and 2.10, respectively). Prior history of varicella infection, varicella vaccination, and contact with cases remained to be associated with the susceptibility after multivariate analysis.

Conclusions: Children who lived in tropical and rural regions and those who had no history of varicella infection, varicella vaccination, and contact with cases, might be more susceptible to varicella. Island-wide VZV seroprevalence surveillance is required to examine whether the geographical difference of susceptibility in Taiwan will become less significant or disappear after the mass varicella vaccination program initiated in 2004.