Travelers and the Flu
The risk for exposure to influenza during travel varies depending on the time of year, destination, and type of travel.
In the tropics, such as the Caribbean, influenza can occur throughout the year. In temperate regions of the Southern Hemisphere, such as parts of Australia and South America, most influenza activity occurs from April through September. In countries of the Northern Hemisphere, such as the United States and Canada, influenza generally occurs from November through March.
However, in temperate climate zones of the Northern and Southern Hemispheres, travelers can be exposed to influenza during their respective summer months, especially when traveling as part of large, organized tourist groups composed of persons from areas of the world where influenza viruses are circulating.