<h2>What should you know about flu (influenza)?</h2>

<p>Flu is caused by the influenza virus. Previous infection or vaccination is no guarantee of protection against it – the flu virus is changing all the time and there are many different strains.</p>

<h3>How serious is flu?</h3>

<p>While most people have relatively mild flu symptoms, flu is a potentially serious disease that can lead to hospitalisation and sometimes even death. It can cause bronchitis, croup, pneumonia, ear infections, heart and other organ damage, brain inflammation and brain damage.</p>
