France has changed from a country where hepatitis A is endemic to one where residents are at risk of hepatitis A infection: in 20 years, the seroprevalence in 20-year-olds has fallen from 50% to less than 10%. Prophylaxis for close contacts of an index case has therefore become a major problem because their risk of hepatitis A is high. Polyvalent immunoglobulins are recommended in several countries, but no immunoglobulins are approved for this indication in France. Immunoglobulins are also expensive and only slightly efficacious. A vaccine against hepatitis A administered to young children or adolescents can break the epidemic chain and protect adults very effectively by limiting virus circulation. Many countries propose early vaccination to at-risk contacts, with vaccination generally advised within a week of the initial infectious contact. Although more specific and more plentiful data are still necessary before this recommendation can be generalized, it must be taken into account. This medical decision should thus be made on an individualized basis after discussion between the physician and family about the risk.