Explanation
The H1N1 virus is often mentioned in the news with reference to the disease known as "influenza" or "swine flu."
H1N1 is a subtype of the influenza A virus that caused a global pandemic in 2009. It is called "swine flu" because the virus was initially transmitted from pigs to humans. Influenza caused by the H1N1 virus can spread from person to person and can result in a range of symptoms, from mild to severe, similar to other strains of the flu.
