Influenza: seasonality and travel-related considerations.

The differences in influenza seasonality between hemispheres have substantial implications for the effectiveness of influenza vaccination of travellers. Health care providers should be aware of influenza activity when patients report travel plans, provide alerts, and advise on prevention, diagnostic and treatment options. To mitigate the risk of travel-related influenza, interventions include antivirals for self-treatment (in combination with the use of rapid self-tests), extending the shelf life of influenza vaccines to enable immunization during the summer months for international travellers, and gaining access to the influenza vaccine used in the opposite hemisphere as a travel-related vaccine. With the currently available vaccines, the most important preventive measure remains optimizing the seasonal influenza vaccination. It is also imperative that influenza is recognized as a travel-related illness, both travellers as well as health care professionals.