H1N1

For information on ways to decrease one's chances of contracting H1N1, see influenza prevention.
For the H1N1/09 virus strain responsible for the 2009 flu pandemic, see Pandemic H1N1/09 virus.
For the current pandemic of Influenza A(H1N1), see 2009 flu pandemic.
For the 1918 pandemic of Influenza A(H1N1), see 1918 flu pandemic.
Influenza (flu)

2009 flu pandemic (Swine flu)
Virus
Avian influenza
Swine influenza
Flu season
Research
Vaccine
Treatment
A/H5N1 subtype
A/H1N1 subtype
Pandemic
Influenza A(H1N1) virus is a subtype of influenzavirus A and the most common cause of influenza (flu) in humans. Some strains of H1N1 are endemic in humans and cause a small fraction of all influenza-like illness and a large fraction of all seasonal influenza. H1N1 strains caused roughly half of all human flu infections in 2006.[1] Other strains of H1N1 are endemic in pigs (swine influenza) and in birds (avian influenza).
In June 2009, World Health Organization declared that flu due to a new strain of swine-origin H1N1 was responsible for the 2009 flu pandemic. This strain is often called "swine flu" by the public media.