Influenza, or the flu, is a highly contagious viral infection. It is most often caused by type A or B (rarely C) influenza viruses that infect the upper airways and lungs. Most flu cases in Australia occur during winter. In tropical and subtropical areas, like Queensland though, the flu is common all year round.
The flu is very serious. For young kids, especially children under 5, people over 65 years of age, pregnant women, and those with medical conditions such as diabetes, lung or heart disease, it can result in hospitalisation or worse.
Most people recover from the flu within a week, although a cough and tiredness can last longer. Serious complications of flu occur in a small number of people. These include pneumonia, inflammation of the heart muscle and neurologic complications.