Influenza is viral disease characterized by a sudden onset of fever, cough, headache, muscle and joint pain, severe malaise, sore throat and a runny nose. While most people recover from these symptoms in about a week without medical attention, there are cases with complications where the illness is severe and can cause death. Influenza spreads around the world in yearly outbreaks, causing about 3 to 5 million cases of severe illness and about 290,000 to 650,000 deaths due to respiratory complications (from WHO). The World Health organization suggests the use of the vaccine in order to protect the people at higher risk (very young children and elderly people, for example), but the immunity given by the vaccine is not lifelong and vaccinations of one year could be ineffective even the next year.