Disease Description: Influenza is caused by infection with influenza virus. Human influenza viruses can be divided into two types: A and B. Illness is characterized by fever, respiratory symptoms, headache, and muscle aches. Illness can be severe.
Risk to Travelers: The risk for exposure to influenza during international travel depends on the time of year and destination. In the tropics, influenza can occur throughout the year, while in the temperate regions it tends to occur in the fall/winter seasons of the respective hemispheres.
Prevention - Vaccine: Influenza vaccine should be recommended before travel for persons at high risk for complications of influenza if 1) influenza vaccine was not received during the preceding fall or winter, 2) travel is planned to the tropics, 3) travel is planned with large groups of tourists at any time of year, or 4) travel is planned to the Southern Hemisphere from April through September.
Vaccine Adverse Effects: The most frequent side effect of vaccination with inactivated vaccine is soreness and redness at the vaccination site that lasts up to 2 days.
Vaccine Contraindications: Persons with history of severe egg allergy should consult with their physician before receiving influenza vaccine.
Vaccine Booster Recommendations: Influenza vaccines must be received annually for individuals to maintain protection against influenza.
Information adapted from CDC Health Information for International Travel (the Yellow Book), http://www.cdc.gov/travel/yellowbook/2010/table-of-contents.htm