Epidemiology and prevention of hepatitis A in travelers.

OBJECTIVE

To assess the risk of hepatitis A in international travelers and to recommend preventive measures.

DATA SOURCES

Index Medicus, 1974 through 1983; MEDLINE, 1984 through 1993; and unpublished data of the Centers for Disease Control and Prevention.

STUDY SELECTION

Review of all retrospective and cohort studies on hepatitis A and other vaccine-preventable diseases in travelers, of seroepidemiologic surveys of hepatitis A virus (HAV) antibodies in travelers, of data on the various hepatitis A vaccines, of economic analyses, and of recommendations of recognized organizations.

DATA EXTRACTION

Independent analysis by multiple observers.

DATA SYNTHESIS

The incidence rate for unprotected travelers, including those staying in luxury hotels, is estimated to be three per 1000 travelers per month of stay in a developing country. Persons eating and drinking under poor hygienic conditions have a rate of 20/1000 per month. This makes hepatitis A the most frequent infection in travelers that may be prevented by immunization. In many industrialized countries persons born after 1945 have an HAV antibody seroprevalence (immunity) of less than 20%. New inactivated HAV vaccines induce protective antibodies in more than 95% of recipients and offer protection estimated to last for 10 years or more, whereas protection by immune globulin lasts only 3 to 5 months.

CONCLUSIONS

Hepatitis A vaccine, or immune globulin where HAV vaccine is not available, is recommended for all nonimmune travelers visiting developing countries. Prescreening for antibodies to HAV in travelers living in countries with low prevalence is usually not necessary in persons born after 1945.