Only yellow fever and cholera vaccinations are required by law for international travel. Although not generally considered "travel" immunizations, routine immunizations are not up to date in many Americans because immunity was allowed to lapse (e.g., dìphtheria-tetanus) or proper immunization was not done in their youth (e. g., measles and polio). Other immunizations are strongly recommended for travel to specific areas.

1. Yellow fever: This live attenuated virus vaccine is recommended for travel to areas in South America and Africa where yellow fever is endemic. It is required by law for travel out of a yellow fever endemíc area into most other countries (not the United States).

2. Cholera: This vaccine is of limited effectiveness, and cholera is not a disease of North American tourists. Vaccination is given only to meet the legal requirement for travel between some Third World countries that have endemic cholera. Because of vicissitudes of international travel (unexpected transit into a neighboring country) and uncertainty of obtaining sterile, disposalbe needles overseas, cholera vaccine is given primarily to protect against unwanted needle sticks in foreign quarantine stations.

3. Measles and mumps: Up to 20 per cent of college freshmen have no serological evidence of prior measles/mumps infection or immunization and must be presumed to be susceptible. Individuals born after 1956 (measles) and 1970 (mumps), with no documented record of immunization, should receive live attenuated virus vaccination.

4. Diphtheria-tetanus: A booster within the last five years eliminnates the need for a tetanus booster if the traveler sustains an injury overseas.