Sero-prevalence of antibodies against varicella zoster virus in children under seven-years old in 2012 in Tehran, Iran

ABSTRACT

Varicella zoster virus [VZV] is a member of herpes family viruses, which causes varicella [chickenpox] after primary infection and herpes zoster [shingles] because of latent virus reactivation from dorsal root ganglia. Generally, prevalence of varicella antibodies increases with age. We aimed to compare the prevalence of anti-VZV antibody in children under seven years old, in order to obtain a preliminarily picture of general presence of these antibodies to design an immunization plan. In this cross-sectional study, performed from September 2011 to September 2012 in Tehran, Iran, 267 serum samples including sera from 7 month old infants, n= 87; 18 month old children, n= 86; and 6 year old children, n= 94 were assessed for the presence of specific IgG antibodies against VZV, using ELISA technique. 4.6% of 7 month, 12.8% of 18 month and 21.3% of 6-year-old children were seropositive. No relation was found between demographic variables [e.g. age and birth weight] and seropositivity in these age groups. VZV antibodies increased with age. Serum levels of varicella antibodies were elevated in 18 months old compared to 7 months old children, significantly [P < 0.001]. In view of the significant elevation of VZV antibodies in children from 7 months to 18 months of age and rate of seronegative children, our results support the necessity of varicella immunization between 7 and 18 months of age in order to prevent viral infection