Hepatitis A seroprevalence in a population of immigrants at a French vaccination center.

Background: Hepatitis A vaccination is recommended to people traveling to countries where the disease is endemic. Until recently, people originating from developing countries were considered to be "naturally" immunized. Because of improving socioeconomic conditions, hepatitis A incidence has decreased in most previously highly endemic countries during the last three decades, especially in the younger age groups.
Methods: We analyzed hepatitis A seroprevalence of 989 travelers who had been born and lived at least 1 year in a developing country, wanted to travel to a hepatitis A endemic area, and consulted at the vaccination center of the Institut Pasteur of Paris between September 1, 2008 and February 28, 2010.
Results: Hepatitis A serology results were available for 646 subjects. Overall seroprevalence was 82.4%. A total of 90, 82.6, 81.2, 68.4, 56.9, and 50% of people of sub-Saharan African, Near and Middle Eastern, North African, Asian, Latin American, and Eastern European origin had hepatitis A antibodies, respectively. The difference in seroprevalence according to the continent of origin, age, and length of stay in an endemic country was significant (p < 0.0001). More than 75% of seronegatives and less than 50% of seropositives were younger than 36 years. Almost three quarters of the positive group (while less than half of the negative group) lived longer than 18 years in a developing country. Multivariate analysis showed that seroprevalence increases with age, length of stay in a country at risk, and varies significantly from one continent to another.
Conclusion: We recommend extending serologic confirmation of immigrants' hepatitis A immunity. If time is lacking, vaccination should be considered.
(© 2011 International Society of Travel Medicine.)