United States epidemiology of hepatitis A: influenced by immigrants visiting friends and relatives in Mexico?

Among the industrialized nations, the United States annually receives the greatest number of immigrants as permanent residents. Immigrants from Mexico have represented the largest segment of the foreign-born population in recent decades, and continued growth of Mexican immigration is predicted for the decades ahead. The changing demographics of this population, including the emergence of new immigrant growth centers, will influence the future epidemiology of hepatitis A virus transmission in the United States. Travel home to the place of origin to visit friends and relatives (VFR) by both newly arrived and established Mexican immigrants constitutes a new group of travelers that now include intergenerational family units. Asymptomatic pediatric travelers-who acquire hepatitis A abroad and are infectious on return to American communities-contribute to the silent transmission of hepatitis A to playmates, caretakers, and contacts in households, daycare facilities, and elementary schools. Considering the expanded geographic distribution of Mexican immigrant settlement, the predicted increased diversity of pediatric populations in the United States over time, and the continued growth of VFR travel, a universal pediatric vaccine recommendation for hepatitis A immunization can help to prevent hepatitis A transmission in this country in the future.