Fighting influenza Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses.To prevent influenza, firstly, vaccination, secondly, good hygiene practices such as washing hands with soap and water regularly, thirdly, following a healthy lifestyle such as maintaining a balanced diet, and getting enough sleep.Prevention is key when it comes to the flu, and simple steps like vaccination, good hygiene, and a healthy lifestyle can go a long way in keeping you flu-free.