Influenza

Seasonal influenza, or flu, is a highly contagious respiratory illness caused by influenza viruses that infect the nose, throat and lungs. The two main types of influenza viruses—types A and B—are the viruses that typically spread in people (human influenza viruses) and cause annual flu outbreaks. Each year, influenza causes millions of illnesses worldwide and, in the United States, results in thousands of hospitalizations and deaths. Influenza is especially dangerous for people 65 years and older, young children and people with certain health conditions, such as heart disease or asthma.  

An influenza pandemic occurs when a new influenza virus emerges that is able to infect and spread easily from person to person and to which most of the global population does not have immunity. The last known influenza pandemic occurred in 2009 with the emergence of the H1N1 influenza virus.  Research to find new and improved ways to diagnose, treat and prevent seasonal influenza and novel influenza viruses with pandemic potential is essential to protecting the public health.