Immunizations for international travelers.

Each year more than 45 million Americans travel abroad for work or pleasure, and over 20 million of these travel to rural areas or developing countries. While the major medical risks of international travel are often exaggerated, the incidence of minor illness is not. Persons going to Asia, Africa, or Latin America for one month run a 65% to 75% chance of becoming ill, although only 1% will require hospitalization. The two most common illnesses that affect travelers, which do have immunizations and are often overlooked by physicians, are influenza and hepatitis A. The risk of illness to the traveler varies by health and age status, by the region to be visited, by the time of year, and by the length of the journey. Immunization advice for the traveler, therefore, is complicated and is best approached in a systematic manner. This article outlines six steps to sound immunization advice. These steps include ascertaining the traveler's special individual needs, routine immunization status, and routine travel immunization status, as well as the entry requirements for the country to be visited, geographically indicated vaccines, and immunizations as indicated for extended stays abroad.