Seroprevalence of Varicella Zoster Infection at Provincial Level in Iranian Adolescents: The CASPIAN-III Study

Abstract

Background: Although primary varicella zoster virus (VZV) infection (chicken pox) is a mild childhood disease, it can cause severe infection with complications in adults. As the disease is preventable by effective vaccination, it is important to determine the level of immunity to VZV in every region to implement proper vaccination strategies. Objectives: The aim of this study was to investigate the seroprevalence of VZV infection in adolescents living in different provinces of Iran. Methods: In a cross-sectional multicentre study, serum samples from 2315 students, aged 10-18 years, were examined for VZV antibodies (IgM/IgG). Students were selected by multistage cluster sampling during a national surveillance program. Results: Prevalence of VZV antibodies was statistically different in various provinces of Iran (P = 0.001); it ranged from 82.4 in Isfahan, Center of Iran, to 98.5 in Mazandaran, North of the country. The VZV seroprevalence was not significantly different by gender, except for Khuzestan, South of Iran, where antibodies were much more prevalent in girls (92.7) than in boys (78.3, P = 0.004). Seroprevalence was not significantly different according to the living area (urban/rural). Conclusions: VZV seroprevalence is different in various provinces of Iran; the susceptibility of adult population to VZV infection is suggested to be high in Ardabil, Isfahan, and Kermanshah; and low in Kerman and Mazandaran. Therefore, different strategies should be implemented in each province to protect high-risk adults from severe varicella infection.