Influenza is a respiratory infection and is transmitted by droplets or by direct contact with objects that have been touched by droplets. Common sense precautions, such as hand washing and avoiding others who are coughing, are an excellent way to avoid getting sick with this illness. Outbreaks of influenza occur during the winter, and the flu season is thought to be active starting in October or November and lasting until March or April in the Northern Hemisphere. The flu season is reversed below the equator, which might be relevant for those traveling below the equator between May and October.
The most critical fact to understand about influenza is that there will be millions of cases each winter. Millions of cases. This is the most common infection for which there is a vaccine, and it is very likely your child will be exposed. Statistically, children are more likely than adults to catch influenza in any given season. This is probably related to their close contact with sick classmates at school. However, children under age five and adults are more likely to be hospitalized than school-aged children.