Review of varicella zoster seroepidemiology in India and Southeast Asia.

Varicella zoster virus (VZV) predominantly affects children in temperate countries, with near-universal seroconversion occurring by late childhood. However, in tropical regions, VZV infection is common in adolescents and adults. This review identifies age-related VZV seroprevalence patterns in a number of Asian countries which indicate that seroconversion in tropical countries occurs at a later age than in temperate countries. Seasonal and regional variations in acute disease within some Asian countries suggest that temperate climates might favour transmission of the varicella virus, with incidence peaking during cooler months and in cooler, more temperate regions. VZV infection is often more severe in adults than in children, suggesting that tropical countries may be at risk of greater morbidity and mortality as a result of later-age seroconversion. Susceptibility of pregnant women and their infants, and of people infected with HIV/AIDS is also cause for concern. Vaccination may be beneficial in reducing the impact of VZV in Asian populations.