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Influenza due to Influenza A virus subtype H1N1

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: H1N1 Flu; H1N1 Influenza; H1N1 Virus Infection; Influenza A (H1N1); Influenza A (H1N1) Virus Infection; Influenza caused by Influenza A virus subtype H1N1; Swine Flu; Swine Influenza
SNOMED CT: Influenza A (H1N1) (442696006); Influenza due to Influenza A virus subtype H1N1 (442696006); Influenza caused by Influenza A virus subtype H1N1 (442696006)


An acute viral respiratory infection caused by a strain of influenza virus which is endemic in swine (pigs). Rarely reported in humans prior to 2009, the disease is caused by a mutated strain of swine influenza A (H1N1) virus. It is highly contagious and spreads mainly through coughing and sneezing. Signs and symptoms include fever, chills, coughing, sore throat headache, muscle ache, and generalized weakness. Antiviral medications are most effective in the first two days of the illness. [from NCI]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVInfluenza due to Influenza A virus subtype H1N1

Professional guidelines


Grohskopf LA, Blanton LH, Ferdinands JM, Chung JR, Broder KR, Talbot HK, Morgan RL, Fry AM
MMWR Recomm Rep 2022 Aug 26;71(1):1-28. doi: 10.15585/mmwr.rr7101a1. PMID: 36006864Free PMC Article
Rewar S, Mirdha D, Rewar P
Ann Glob Health 2015 Sep-Oct;81(5):645-53. doi: 10.1016/j.aogh.2015.08.014. PMID: 27036721
Herold S, Becker C, Ridge KM, Budinger GR
Eur Respir J 2015 May;45(5):1463-78. Epub 2015 Mar 18 doi: 10.1183/09031936.00186214. PMID: 25792631

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