H1N1 Influenza, commonly known as swine flu, is a respiratory illness caused by the H1N1 virus. It was first identified in 2009 and can spread from person to person, similar to seasonal flu. Symptoms include fever, cough, sore throat, body aches, and fatigue. Vaccines are available to help prevent H1N1 Influenza, and public health measures, such as handwashing and avoiding close contact with sick individuals, can reduce transmission. Most people recover without needing medical treatment, but severe cases can occur, particularly in high-risk groups like young children, the elderly, and those with underlying health conditions.