The Seroprevalence of Varicella Zoster Virus in a Healthy Population from Tehran, Iran

Abstract

Background: Varicella zoster virus (VZV) is responsible for chickenpox, which is generally a mild self-limited disease in healthy children. However, this disease may progress to a complicated and even life-threatening disease in adolescents, young adults, and immunocompromised patients in particular. The present study was conducted to investigate the seroprevalence of VZV in different age groups, selected among residents of Tehran, Iran. Methods: We performed varicella serological tests (IgG) on the serum specimens of healthy people, collected from 3 main laboratories in Tehran. VZV IgG was measured with the ELISA method. We divided the subjects into 6 subgroups: below 2 years, 2 - 5 years, 5 - 12 years, 12 - 19 years, 19 - 25 years, and above 25 years. We tested almost 95 specimens from each age group. Results: Samples were collected from 570 individuals, including 231 males. The VZV IgG was positive in 393 subjects; cumulatively, 81.3% of the population were immune to VZV. The seroprevalence rate was 43.2% in infants below 2 years, 32.6% in children aged 2 - 5 years, 47.2% in children aged 5 - 12 years, 74.7% in adolescents aged 12 - 19 years, 83.2% in young adults up to 25 years, and 90.5% in adults > 25 years. Conclusions: Although the cumulative seroprevalence was estimated at 81.3% for all age groups, this rate was only 43% in children below 12 years; therefore, adolescents and young adults (high-risk age groups) are prone to chickenpox infection. In order to protect individuals against this infection, we suggest well-designed studies to address the need for routine chickenpox immunization programs in young children.