Immunity to hepatitis A in people born and raised in endemic areas

Hepatitis A is the most common vaccine-preventable disease in international travelers. Many individuals born and raised in hepatitis A endemic areas are likely to be immune to hepatitis A. Unnecessary hepatitis A immunization could be avoided by taking into account prior exposure to hepatitis A and judicious use of serotesting prior to immunization.

Patients born and raised in countries of high prevalence of hepatitis A who were seen for pretravel consultation and who had hepatitis antibody measured were eligible. Data were collected about country of birth and length of residence there before emigration, length of time till departure on current trip, current age, and hepatitis A antibody result.

Patients ranged from 12 to 74 years of age and were from 27 countries. Their pretravel visit occurred from 4 to more than 90 days prior to departure. Ninety-five percent (122 of 129) of patients were immune to hepatitis A, including 100% (83 of 83) of those who resided in their country of origin until at least aged 20. Most patients were seen for pretravel consultation less than 28 days prior to departure.

Individuals born and raised until aged 20 in hepatitis A endemic countries are likely to be immune to hepatitis A. Serotesting is most helpful in assessing immunity to hepatitis A in those under 20 years of age.