Strategies to Prevent Varicella among Newly Arrived Adult Immigrants and Refugees: A Cost-Effectiveness Analysis

In temperate, industrialized countries, such as Canada, varicella is a common disease in childhood [1]. In tropical countries, for reasons that are not entirely clear, varicella occurs among young adults. Seroprevalence data from tropical regions suggest that up to 30% of individuals are susceptible to varicella at 20 years of age, and 5%-10% remain susceptible at 30 years of age [2, 3]. There have been many reported outbreaks of varicella in immigrant populations in industrialized countries, suggesting that foreign-born adults are disproportionately susceptible [4-6]. Recent immigrants also have a high risk of exposure, because many are the parents of young children, who have a high annual incidence of varicella unless they are vaccinated. Varicella is more severe in adults than in children