Consult the medical resource doctors trust

UpToDate is one of the most respected medical information resources in the world, used by over 360,000 doctors and thousands of patients to find answers to medical questions.

  • Content written by a faculty of over 4,000 physicians from leading medical institutions
  • Unbiased: free of advertising or pharmaceutical funding
  • Evidence-based treatment recommendations
  • Continuously updated to incorporate new medical findings

Treatment of pandemic H1N1 influenza ('swine influenza')

INTRODUCTION

In late March and early April 2009, an outbreak of H1N1 influenza A virus infection was detected in Mexico, with subsequent cases observed in many other countries, including the United States [1,2]. On June 11, 2009, the World Health Organization raised its pandemic alert level to the highest level, phase 6, indicating widespread community transmission on at least two continents [3]. (See "Epidemiology, clinical manifestations, and diagnosis of pandemic H1N1 influenza ('swine influenza')", section on '2009 pandemic'.)

The pandemic that began in March 2009 was caused by an H1N1 influenza A virus that represents a quadruple reassortment of two swine strains, one human strain, and one avian strain of influenza. (See "Epidemiology, clinical manifestations, and diagnosis of pandemic H1N1 influenza ('swine influenza')", section on 'Genetic and antigenic characterization'.)

The treatment of pandemic H1N1 influenza A virus infection will be reviewed here. The epidemiology, clinical manifestations, diagnosis, and prevention of pandemic H1N1 influenza A virus infection, and the treatment and prevention of seasonal and avian (H5N1) influenza virus infections, are discussed separately. (See "Epidemiology, clinical manifestations, and diagnosis of pandemic H1N1 influenza ('swine influenza')" and "Prevention of pandemic H1N1 influenza ('swine influenza')" and "Treatment of seasonal influenza in adults" and "Antiviral drugs for the prevention and treatment of influenza in children" and "Prevention of seasonal influenza in adults" and "Treatment and prevention of avian influenza".)

DEFINITIONS

Case definitions — The following case definitions have been provided by the United States Centers for Disease Control and Prevention [4]:

  • Influenza-like illness (ILI) is defined as fever (temperature of 100ºF [37.8ºC] or greater) with cough or sore throat in the absence of a known cause other than influenza.
  • A confirmed case of pandemic H1N1 influenza A is defined as an individual with an ILI with laboratory-confirmed H1N1 influenza A virus detected by real-time reverse transcriptase (rRT)-PCR or culture.
  • Pandemic H1N1 influenza A may be suspected in an individual who does not meet the definition of confirmed pandemic H1N1 influenza A, but has an ILI and an epidemiologic link.
To continue reading this article you need to subscribe.

Read the rest of this article and others like it

The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use (click here) ©2009 UpToDate, Inc.
References Top
  1. Update: novel influenza A (H1N1) virus infections - worldwide, May 6, 2009. MMWR Morb Mortal Wkly Rep 2009; 58:453.
  2. World Health Organization. Pandemic (H1N1) 2009 - update 58, 6 July 2009. http://www.who.int/csr/don/2009_07_06/en/index.html (Accessed July 7, 2009).
  3. World Health Organization. World now at the start of 2009 influenza pandemic. http://www.who.int/mediacentre/news/statements/2009/h1n1_pandemic_phase6_20090611/en/index.html (Accessed June 11, 2009).
  4. United States Centers for Disease Control and Prevention. Interim guidance on case definitions to be used for investigations of novel influenza A (H1N1) cases. http://www.cdc.gov/h1n1flu/casedef.htm (Accessed June 2, 2009).
  5. United States Centers for Disease Control and Prevention. Interim guidance for clinicians on identifying and caring for patients with swine-origin influenza A (H1N1) virus infection http://www.cdc.gov/swineflu/identifyingpatients.htm (Accessed May 5, 2009).
  6. United States Centers for Disease Control and Prevention. Updated interim recommendations for obstetric health care providers related to use of antiviral medications in the treatment and prevention of influenza for the 2009-2010 season. http://www.cdc.gov/H1N1flu/pregnancy/antiviral_messages.htm (Accessed November 3, 2009).
  7. United States Centers for Disease Control and Prevention. Interim guidance—HIV-infected adults and adolescents: Considerations for clinicians regarding novel influenza A (H1N1) virus. http://www.cdc.gov/h1n1flu/guidance_HIV.htm (Accessed October 27, 2009).
  8. United States Centers for Disease Control and Prevention. H1N1 flu and patients with cardiovascular disease (heart disease and stroke): Interim guidance and considerations for health care providers and for state and local public health agencies. http://www.cdc.gov/h1n1flu/guidance/cardiovascular.htm (Accessed May 3, 2009).
  9. United States Centers for Disease Control and Prevention. Interim guidance for clinicians on the prevention and treatment of novel influenza A (H1N1) influenza virus Infection in infants and young children. http://www.cdc.gov/h1n1flu/childrentreatment.htm (Accessed September 11, 2009).
  10. United States Centers for Disease Control and Prevention. Updated interim recommendations for the use of antiviral medications in the treatment and prevention of influenza for the 2009-2010 season. http://www.cdc.gov/h1n1flu/recommendations.htm (Accessed October 19, 2009).
  11. United States Centers for Disease Control and Prevention. People at high risk of developing flu-related complications. http://www.cdc.gov/h1n1flu/highrisk.htm (Accessed October 13, 2009).
  12. United States Centers for Disease Control and Prevention. 2009 H1N1 flu (referred to as "swine flu" early on) and seasonal flu information for rheumatology health professionals. http://www.cdc.gov/h1n1flu/arthritis_clinicians.htm (Accessed October 19, 2009).
  13. Intensive-care patients with severe novel influenza A (H1N1) virus infection - Michigan, June 2009. MMWR Morb Mortal Wkly Rep 2009; 58:749.
  14. World Health Organization. Human infection with pandemic A (H1N1) 2009 influenza virus: clinical observations in hospitalized patients, Americas, July 2009 - update. Weekly epidemiological record 2009. http://www.who.int/wer/2009/wer8430/en/index.html (Accessed August 11, 2009).
  15. Louie, JK, Acosta, M, Winter, K, et al. Factors associated with death or hospitalization due to pandemic 2009 influenza A (H1N1) infection in California. JAMA 2009; 302:1896.
  16. United States Centers for Disease Control and Prevention. CDC Health Alert Network (HAN) info service message: key issues for clinicians concerning antiviral treatments for 2009 H1N1. http://www.cdc.gov/H1N1flu/HAN/110609.htm (Accessed November 10, 2009).
  17. The Commonwealth of Massachusetts Department of Public Health. Interim guidance on testing and antiviral treatment for influenza H1N1. http://www.mass.gov/Eeohhs2/docs/dph/cdc/flu/swine_interim_guidance_testing_and_antiviral_treatment.pdf (Accessed May 5, 2009).
  18. Jain, S, Kamimoto, L, Bramley, AM, et al. Hospitalized patients with 2009 H1N1 influenza in the United States, April-June 2009. N Engl J Med 2009; [Epub ahead of print].
  19. Dominguez-Cherit, G, Lapinsky, SE, Macias, AE, et al. Critically Ill Patients With 2009 Influenza A(H1N1) in Mexico. JAMA 2009; 302:1880.
  20. World Health Organization. Influenza-like illness in the United States and Mexico, 24 April 2009. http://www.who.int/csr/don/2009_04_24/en/index.html (Accessed April 27, 2009).
  21. Update: drug susceptibility of swine-origin influenza A (H1N1) viruses, April 2009. MMWR Morb Mortal Wkly Rep 2009; 58:433.
  22. World Health Organization. Viruses resistant to oseltamivir (Tamiflu) identified, 8 July 2009. http://www.who.int/csr/disease/swineflu/newsbriefs/h1n1_antiviral_resistance_20090708/en/index.html (Accessed July 8, 2009).
  23. United States Centers for Disease Control and Prevention. 2009-2010 influenza season week 43 ending October 31, 2009. http://www.cdc.gov/flu/weekly/index.htm#whomap (Accessed November 10, 2009).
  24. Los Angeles Times. Health officials to increase testing of swine flu for Tamiflu resistance after US case. http://www.latimes.com/news/nationworld/nation/wire/sns-ap-us-med-swine-flu,1,2816215.story (Accessed July 8, 2009).
  25. The Canadian Press. Quebec finds first, Japan finds second cases of Tamiflu-resistant swine flu. http://www.google.com/hostednews/canadianpress/article/ALeqM5gaNQxQtkte8cDFnwA_JRXyesKjAQ (Accessed July 23, 2009).
  26. Oseltamivir-Resistant Novel Influenza A (H1N1) Virus Infection in Two Immunosuppressed Patients --- Seattle, Washington, 2009. MMWR Morb Mortal Wkly Rep 2009; 58:893.
  27. World Health Organization. Pandemic (H1N1) 2009 - update 62 (revised 21 August 2009) http://www.who.int/csr/don/2009_08_21/en/index.html (Accessed August 25, 2009).
  28. Oseltamivir-resistant 2009 pandemic influenza A (H1N1) virus infection in two summer campers receiving prophylaxis--North Carolina, 2009. MMWR Morb Mortal Wkly Rep 2009; 58:969.
  29. United States Food and Drug Administration. Emergency use authorization (EUA) for the investigational antiviral drug peramivir. http://www.fda.gov/downloads/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/UCM187800.pdf (Accessed October 26, 2009).
  30. United States Centers for Disease Control and Prevention. antiviral treatment options, including intravenous peramivir, for treatment of influenza in hospitalized patients for the 2009-2010 season. http://www.cdc.gov/h1n1flu/EUA/peramivir_recommendations.htm (Accessed October 26, 2009).
  31. Ison, MG, McGeer, A, Hui, DS, et al. Safety and efficacy of multiple-day treatment with intravenous peramivir or oral oseltamivir in hospitalized adults with acute influenza. XI International Symposium on Respiratory Viral Infections. 2009. Oral abstract available at http://www.themacraegroup.com/2009-symposia/xi-international-symposium-on-respiratory-viral-infections/oral-abstracts/safety-and-efficacy-of-multiple-day-treatment-with-intravenous-peramivir-or-oral-oseltamivir-in-hospitalized-adults-with-acute-influenza (Accessed October 27, 2009).
  32. Kohno, S, et al. Single-intravenous peramivir vs. oral oseltamivir to treat acute, uncomplicated influenza in the outpatient setting: a phase III randomized, double-blind trial. Abstract V-537a. 49th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco, CA September 12-15, 2009.
  33. United States Food and Drug Administration. MedWatch Safety Alert. Relenza (zanamivir) inhalation powder. www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm186081.htm (Accessed October 9, 2009).
  34. United States Centers for Disease Control and Prevention. Emergency use authorization of peramivir IV - fact sheet for health care providers. http://www.cdc.gov/h1n1flu/eua/Final%20HCP%20Fact%20sheet%20Peramivir%20IV_CDC.pdf (Accessed October 27, 2009).
  35. FDA News Release. FDA warns of unapproved and illegal H1N1 drug products purchased over the internet. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm186861.htm (Accessed October 19, 2009).
  36. Tanaka, T, Nakajima, K, Murashima, A, et al. Safety of neuraminidase inhibitors against novel influenza A (H1N1) in pregnant and breastfeeding women. CMAJ 2009; 181:55.
  37. Rasmussen, SA, Jamieson, DJ, Macfarlane, K, et al. Pandemic influenza and pregnant women: summary of a meeting of experts. Am J Public Health 2009; :.
  38. Moretti, ME, Bar-Oz, B, Fried, S, Koren, G. Maternal hyperthermia and the risk for neural tube defects in offspring: systematic review and meta-analysis. Epidemiology 2005; 16:216.
  39. United States Centers for Disease Control and Prevention. Recommendations for use of antiviral medications for the management of influenza in children and adolescent for the 2009-2010 season - pediatric supplement for health care providers. http://www.cdc.gov/h1n1flu/recommendations_pediatric_supplement.htm (Accessed October 19, 2009).
  40. United States Centers for Disease Control and Prevention. Emergency Use Authorization of Tamiflu (oseltamivir). http://www.cdc.gov/h1n1flu/eua/tamiflu.htm (Accessed September 11, 2009).
  41. United States Food and Drug Administration. Emergency use authorization (EUA) review - oseltamivir phosphate for swine influenza A. http://www.fda.gov/downloads/Drugs/DrugSafety/InformationbyDrugClass/UCM153547.pdf (Accessed September 11, 2009).
  42. Tamiflu (oseltamivir) for oral suspension: potential medication errors. www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm183714.htm (Accessed September 28, 2009).
  43. FDA Public Health Alert: Potential medication errors with Tamiflu for oral suspension. www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm183649.htm (Accessed September 28, 2009).
  44. United States Centers for Disease Control and Prevention. Questions & answers: antiviral drugs, 2009-2010 flu season. http://www.cdc.gov/h1n1flu/antiviral.htm (Accessed October 26, 2009).
  45. Chan-Tack, KM, Murray, JS, Birnkrant, DB. Use of ribavirin to treat influenza. N Engl J Med 2009; 361:1713.
  46. Vandermeer, M, Thomas, A, Kamimoto, L, et al. Role of statins in preventing death among patients hospitalized with lab-confirmed influenza infections. Infectious Diseases Society of America 47th annual meeting, October 29 to November 1, 2009 - oral abstract 706. http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=09faaa5b-1623-4bf1-8edf-7ba49da11c36&cKey=0f97f4e4-5520-4c91-86ff-db4c23129b21 (Accessed November 3, 2009).
white circle LOG IN
white circle DEMO