It's a disease caused by a virus which is passed from person to person by a sneeze or cough. Symptoms include fever, cough, sore throat, fatigue, muscle aches and headache.
Most healthy adults recover from influenza within a few days.
But some people, especially those aged 65 and over, and those with certain chronic illnesses like heart or lung disease, can develop complications. These can include pneumonia or heart failure which can be fatal. If you're over 65, yes. Even if you look and feel very healthy, you're still at risk of catching this virus. If you're under 65, but have a chronic illness, ask your doctor if you need the vaccine.