Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

H1N1 Influenza (Swine Flu) Medication

  • Author: Michael Stuart Bronze, MD; Chief Editor: Russell W Steele, MD  more...
 
Updated: Feb 22, 2016
 

Medication Summary

Laboratory testing has found the H1N1 influenza A (swine flu) virus susceptible to the prescription antiviral drugs oseltamivir and zanamivir. Other antiviral agents (eg, amantadine, rimantadine) are not recommended because of recent resistance to other influenza strains documented over the past several years.

The usual vaccine for influenza administered at the beginning of the flu season is not effective for this viral strain. Also, other antiviral agents (eg, amantadine, rimantadine) are not recommended because of recent resistance to other influenza strains documented over the past several years.

Basic supportive care (ie, hydration, analgesics, cough suppressants) should be prescribed. Empiric antiviral treatment should be considered for confirmed, probable, or suspected cases of H1N1 influenza. Treatment of hospitalized patients and patients at higher risk for influenza complications should be prioritized.

WHO guidelines

WHO guidelines recommend treating serious cases immediately.[27] The guidelines represent an international panel of experts who reviewed all available studies regarding antiviral agents (with emphasis on oseltamivir and zanamivir). Evidence indicates that oseltamivir, when properly prescribed, significantly decreases risk of pneumonia (a leading cause of death for both pandemic and seasonal influenza) and the need for hospitalization.

In the 2009 H1N1 pandemic, oseltamivir-resistant strains were observed in a small number of patients. Most oseltamivir resistance occurred in severely immunocompromised patients with prior exposure to oseltamivir.[28]

For patients who initially present with severe illness or whose condition begins to deteriorate, initiate oseltamivir as soon as possible. For patients with severe or deteriorating illness, treatment should be provided even if started later. Where oseltamivir is unavailable or cannot be used for any reason, zanamivir may be given. This recommendation applies to all patient groups, including pregnant women, and all age groups, including young children and infants.

For patients with underlying medical conditions that increase the risk of more severe disease, WHO recommends treatment with either oseltamivir or zanamivir. These patients should also receive treatment as soon as possible after symptom onset, without waiting for the results of laboratory tests. Pregnant women are included among groups at increased risk, and WHO recommends that pregnant women receive antiviral treatment as soon as possible after symptom onset.

At the same time, the presence of underlying medical conditions will not reliably predict all or even most cases of severe illness. Worldwide, around 40% of severe cases are now occurring in previously healthy children and adults, usually younger than 50 years. Some of these patients experience a sudden and very rapid deterioration in their clinical condition, usually on day 5 or 6 following the onset of symptoms.

Clinical deterioration is characterized by primary viral pneumonia, which destroys the lung tissue and does not respond to antibiotics, and the failure of multiple organs, including the heart, kidneys, and liver. These patients require management in intensive care units using therapies in addition to antivirals.

Peramivir, an investigational, intravenous neuraminidase inhibitor in Phase 3 clinical trials, has been used successfully in adults and children under an emergency investigational new drug program in the United States. It was well tolerated and associated with recovery in the majority of patients hospitalized with severe H1N1 infection.[29]

Initiate antiviral agents within 48 hours

Prompt initiation of antiviral agents within 48 hours of symptom onset is imperative for providing treatment efficacy against influenza virus. In studies of seasonal influenza, evidence for benefits of treatment is strongest when treatment is started within 48 hours of illness onset. However, some studies of treatment of seasonal influenza have indicated benefit, including reductions in mortality or duration of hospitalization, even in patients in whom treatment was started more than 48 hours after illness onset. The recommended duration of treatment is 5 days.[30, 31]

Prophylaxis with antiviral agents should also be considered in the following individuals (pre-exposure or postexposure):

  • Close household contacts of a confirmed or suspected case who are at high risk for complications (eg, chronic medical conditions, persons >65 y or < 5 y, pregnant women)
  • School children at high risk for complications who have been in close contact with a confirmed or suspected case
  • Travelers to Mexico who are at high risk for complications (eg, chronic medical conditions, persons >65 y or < 5 y, pregnant women)
  • Health care providers or public health workers who were not using appropriate personal protective equipment during close contact with a confirmed or suspected case
  • In September 2009, the CDC updated recommendations concerning the use of antiviral medications for prevention because of reported oseltamivir resistance; antivirals should not be used for postexposure chemoprophylaxis in healthy children or adults to manage outbreaks in the community, school, camp, or other settings. [32]
  • Reserve antiviral chemoprophylaxis for persons at higher risk for influenza-related complications who have had contact with someone likely to have been infected with influenza.

Pre-exposure prophylaxis can be considered in the following persons:

  • Any health care provider who is at high risk for complications (eg, persons with chronic medical conditions, adults >65 y, pregnant women)
  • Individuals not considered to be at high risk but who are nonetheless traveling to Mexico, first responders, or border workers who are working in areas with confirmed cases
  • Oseltamivir ring prophylaxis can be considered for outbreaks of pandemic H1N1 influenza A, especially among closed populations such as military personnel; ring prophylaxis involved the use of oseltamivir 75 mg once daily to members of the same military unit where contact opportunities were substantial. [33]

Pediatric considerations

Aspirin or aspirin-containing products (eg, bismuth subsalicylate [Pepto Bismol]) should not be included in the treatment of confirmed or suspected viral infection in persons aged 18 years or younger because of the risk of Reye syndrome. For relief of fever, other antipyretic medications (eg, acetaminophen, nonsteroidal anti-inflammatory drugs) are recommended.

Pregnant women

Oseltamivir and zanamivir are "Pregnancy Category C" medications, indicating that no clinical studies have been conducted to assess the safety of these medications in pregnant women.

Because of the unknown effects of influenza antiviral drugs on pregnant women and their fetuses, oseltamivir or zanamivir should be used during pregnancy only if the potential benefit justifies the potential risk to the embryo or fetus; the manufacturers' package inserts should be consulted. However, no adverse effects have been reported among women who received oseltamivir or zanamivir during pregnancy or among infants born to women who have received oseltamivir or zanamivir.

Prompt use of antiviral drugs during the 2009 H1N1 influenza pandemic improved survival among severely ill pregnant women. The CDC examined reports of severe flu (resulting in death or ICU admission) in 347 pregnant women during the pandemic, including 272 who were admitted to the ICU and survived and 75 who died. Severely ill postpartum women (n=15), including 9 who died, also were reported.

Of the 307 pregnant women for whom information regarding the presence of underlying medical conditions was available, half had underlying conditions such as asthma, diabetes, or hypertension. Among those who died, 86.1% received antiviral treatment with oseltamivir or zanamivir, compared with 94.8% of survivors. Time to initiate treatment from symptom onset was significantly different for women who died, compared with those who survived (P < .01). Only 4 women (7%) of those who died received an antiviral within 2 days of symptom onset, compared with 41% of survivors.

This analysis reaffirms the importance of prevention (ie, vaccination of pregnant women regardless of trimester) and prompt treatment with a neuraminidase inhibitor (ie, within 2 d of symptom onset) if influenza occurs during pregnancy.[34]

Pregnancy should not be considered a contraindication to oseltamivir or zanamivir use. Because zanamivir is an inhaled medication and has less systemic absorption, some experts prefer zanamivir over oseltamivir for use in pregnant women, when feasible.[30, 35] Others recommend that, because pregnant women may have a decreased ability to inhale zanamivir, they should be given oseltamivir.

Next

Antiviral Agent

Class Summary

Drugs indicated for treatment of H1N1 influenza A virus include neuraminidase inhibitors (ie, oseltamivir and zanamivir).

Oseltamivir and zanamivir inhibit neuraminidase, which is a glycoprotein on the surface of influenza virus that destroys an infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, these agents decrease the release of viruses from infected cells and, thus, viral spread.

These antivirals are effective in the treatment of influenza A or B and must be administered within 48 hours of symptom onset to provide optimal treatment. The sooner the drug is administered after symptom onset, the better the likelihood of a good outcome. However, some studies of treatment of seasonal influenza have indicated benefit, including reductions in mortality or duration of hospitalization even for patients whose treatment was started more than 48 hours after illness onset.[30] Antivirals reduce the length of illness by an average of 1.5 days. (In a subgroup of high-risk patients, illness was reduced by 2.5 d.) In addition, the severity of symptoms is also reduced.

On October 23, 2009, the FDA announced emergency-use authorization of the investigational intravenous neuraminidase inhibitor, peramivir. In an observational study of 31 patients, intravenous peramivir was administered to patients with progressive H1N1 pneumonia despite treatment with oseltamivir.[29] Peramivir was well-tolerated, and the 56-day survival rate was 59%. Further studies are necessary to evaluate the effectiveness of peramivir. To request peramivir, see the information at the CDC's H1N1 website or call (800) CDC-INFO (232-4636).

Oseltamivir (Tamiflu)

 

Inhibits neuraminidase, which is a glycoprotein on the surface of influenza virus that destroys an infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, decreases release of viruses from infected cells and thus viral spread. Effective to treat influenza A or B. Start within 40 h of symptom onset. Available as 30-mg, 45-mg, and 75-mg oral capsules and as a powder for suspension that contains 12 mg/mL after reconstitution.

Zanamivir (Relenza)

 

Inhibitor of neuraminidase, which is a glycoprotein on the surface of the influenza virus that destroys the infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, release of viruses from infected cells and viral spread are decreased. Effective against both influenza A and B. Inhaled through Diskhaler oral inhalation device. Circular foil discs containing 5-mg blisters of drug are inserted into supplied inhalation device.

Individuals with asthma or other respiratory conditions that may decrease ability to inhale the drug should be given oseltamivir (eg, asthma, pregnancy). Severe respiratory failure caused by H1N1 influenza has been reported in the southern hemisphere during July and August 2009; therefore, in severely ill patients, the ability to inhale zanamivir may be impaired.

Peramivir (investigational)

 

Investigational neuraminidase inhibitor. Emergency-use authorization issued by US FDA for use of peramivir in hospitalized adult and pediatric patients with suspected or laboratory-confirmed 2009 H1N1 influenza unresponsive to oseltamivir or zanamivir, unable to take PO or inhaled drugs (or delivery route not dependable or feasible), or other circumstances determined by clinician. To request peramivir, see information at www.cdc.gov/h1n1flu/eua or call (800) CDC-INFO (232-4636).

Previous
Next

Vaccines

Class Summary

A systematic review and meta-analysis has reported on the immunogenicity and safety of the 2009 influenza A (H1N1) vaccine. No death or case report of Guillain-Barre was reported and the vaccine, with or without adjuvant, appeared to be generally seroprotective after one dose among those aged older than 36 months.[36]

Each year in the United States, a vaccine that contains antigens from the strains most likely to cause infection during the winter flu season is produced. For the trivalent formulation influenza vaccines, 2 strains of influenza A and 1 of influenza B are included. The quadrivalent vaccines contain an additional influenza B strain.[37] The trivalent 2013-2014 northern hemisphere vaccine contains the following components:

- A/California/7/2009 (H1N1)-like (same strain as was used for 2009 H1N1 monovalent vaccines)

- A/Texas/50/2012 (H3N2), replaces A/Victoria/361/2011

- B/Massachusetts/2/2012-like (B/Yamagata lineage), replaces B/Wisconsin/1/2010-like

The quadrivalent influenza vaccines contain the following additional B strain in addition to the 3 viral strains listed above:

- B/Brisbane/60/2008-like (B/Victoria lineage)

The vaccine is available in a variety of dosage forms. The IM injection contains 45 mcg of hemagglutinin of influenza per 0.5 mL and uses a 1- to 1.5-inch needle. A microinjection system for intradermal delivery (Fluzone Intradermal) features an ultrafine needle that is 90% shorter than the typical needle used for IM injections. The intradermal dosage form contains 27 mcg/0.1 mL of influenza hemagglutinin. In both younger and older adults, the AS03 adjuvant system improves immune response to inactivated 2009 H1N1 influenza vaccine. The AS03 adjuvant system is well tolerated.[38]

Influenza vaccine is also available as a quadrivalent nasal spray (FluMist Quadrivalent) for healthy children 2 years or older, adolescents, and adults younger than 50 years. Clinical trials are limited in scope regarding the protective effects of live vaccine. The live virus is attenuated by cold; therefore, only very limited viral replication occurs at temperatures of more than 95°F.

A recombinant trivalent vaccine (Flublok) is also available for adults aged 18-49 years. It is made from hemagglutinin proteins that are not derived from egg or chick embryo.

Influenza virus vaccine trivalent (Afluria, FluLaval, Fluarix, Flucelvax, Fluvirin, Fluzone, Fluzone High-Dose, Fluzone Intradermal)

 

Influenza vaccine is indicated for active immunization to prevent infection from influenza A and B viruses. The vaccine induces antibodies specific to virus strains contained in the vaccine. The US Public Health Service determines influenza vaccine contents annually. Typically, 3 live attenuated virus strains, which antigenically represent the influenza strains likely to circulate the next flu season, are included in the formulation each year. Fluzone is approved for children as young as 6 months, Fluarix for children aged 3 years or older, Fluvirin for children aged 4 years or older, and Afluria for children aged 5 years or older.

Influenza virus vaccine trivalent, recombinant (Flublok)

 

This vaccine is made from recombinant hemagglutinin proteins that are not derived from egg or chick embryo. Influenza vaccine is indicated for active immunization to prevent infection from influenza A and B viruses. The vaccine induces antibodies specific to virus strains contained in the vaccine. The US Public Health Service determines influenza vaccine contents annually. Typically, 3 live attenuated virus strains, which antigenically represent the influenza strains likely to circulate the next flu season, are included in the formulation each year. It is administered as an IM injection and approved for adults aged 18-49 years.

Influenza virus vaccine quadrivalent (Fluarix Quadrivalent)

 

Quadrivalent vaccines contain 2 strains of influenza A and 2 strains of influenza B. The vaccine induces antibodies specific to virus strains contained in the vaccine. Each year, the US Public Health Service determines which viral strains will be included in the seasonal influenza vaccine that will antigenically represent the viral strains most likely to circulate in the next flu season. It is administered as an IM injection and approved for adults and children 3 years or older.

Influenza virus vaccine quadrivalent, intranasal (FluMist Quadrivalent)

 

The intranasal influenza vaccine is indicated for active immunization to prevent influenza A and B viruses in healthy children, adolescents, and adults. Quadrivalent vaccines contain 2 strains of influenza A and 2 strains of influenza B. The vaccine induces antibodies specific to virus strains contained in the vaccine. Each year, the US Public Health Service determines which viral strains will be included in the seasonal influenza vaccine that will antigenically represent the viral strains most likely to circulate in the next flu season.

Previous
 
 
Contributor Information and Disclosures
Author

Michael Stuart Bronze, MD David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American Medical Association, Oklahoma State Medical Association, Southern Society for Clinical Investigation, Association of Professors of Medicine, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Chief Editor

Russell W Steele, MD Clinical Professor, Tulane University School of Medicine; Staff Physician, Ochsner Clinic Foundation

Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, Southern Medical Association

Disclosure: Nothing to disclose.

References
  1. CDC. Interim Guidance for Clinicians on the Prevention and Treatment of Swine-Origin Influenza Virus Infection in Young Children. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/swineflu/childrentreatment.htm. Accessed: April 30, 2009.

  2. CDC. Interim Guidance on Specimen Collection and Processing for Patients with Suspected Swine Influenza A (H1N1) Virus Infection. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/swineflu/specimencollection.htm. Accessed: April 28, 2009.

  3. Taubenberger JK, Morens DM. 1918 Influenza: the mother of all pandemics. Emerg Infect Dis. 2006 Jan. 12(1):15-22. [Medline].

  4. Bresee J. CDC Podcasts: Swine Flu. Centers for Disease Control and Prevention. Available at http://www2c.cdc.gov/podcasts/player.asp?f=11226. Accessed: April 28, 2009.

  5. Roan S. Swine flu 'debacle' of 1976 is recalled. LA Times. April 27, 2009. Available at http://articles.latimes.com/2009/apr/27/science/sci-swine-history27.

  6. CDC. Swine Flu - Vaccine Safety and Emergency Preparedness. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/vaccinesafety/emergency/swineflu.htm. Accessed: April 29, 2009.

  7. Vellozzi C, Burwen DR, Dobardzic A, Ball R, Walton K, Haber P. Safety of trivalent inactivated influenza vaccines in adults: background for pandemic influenza vaccine safety monitoring. Vaccine. 2009 Mar 26. 27(15):2114-20. [Medline].

  8. Nachamkin I, Shadomy SV, Moran AP, Cox N, Fitzgerald C, Ung H, et al. Anti-ganglioside antibody induction by swine (A/NJ/1976/H1N1) and other influenza vaccines: insights into vaccine-associated Guillain-Barré syndrome. J Infect Dis. 2008 Jul 15. 198(2):226-33. [Medline].

  9. World Health Organization. Influenza-like illness in the United States and Mexico. WHO Epidemic and Pandemic Alert and Response. Available at http://www.who.int/csr/don/2009_04_24/en/index.html. Accessed: April 27, 2009.

  10. WHO. Influenza A (H1N1): Special Insights. World Health Organization. Available at http://www.who.int/en/. Accessed: September 1, 2009.

  11. McNeil DG Jr. U.S. Declares Public Health Emergency Over Swine Flu. New York Times. April 27, 2009. Available at http://www.nytimes.com/2009/04/27/world/27flu.html?th&emc=th.

  12. Swine influenza A (H1N1) infection in two children--Southern California, March-April 2009. MMWR Morb Mortal Wkly Rep. 2009 Apr 24. 58(15):400-2. [Medline]. [Full Text].

  13. U.S. Department of Health and Human Services. Determination That a Public Health Emergency Exists. Available at http://www.hhs.gov/secretary/phe_swh1n1.html. Accessed: April 27, 2009.

  14. CDC. Swine Influenza (Flu). Centers for Disease Control and Prevention. Available at http://www.cdc.gov/h1n1flu/. Accessed: September 1, 2009.

  15. Dawood FS, Jain S, Finelli L, Shaw MW, Lindstrom S, Garten RJ, et al. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med. 2009 Jun 18. 360(25):2605-15. [Medline].

  16. Centers for Disease Control and Prevention (CDC). Update: novel influenza A (H1N1) virus infections - worldwide, May 6, 2009. MMWR Morb Mortal Wkly Rep. 2009 May 8. 58(17):453-8. [Medline].

  17. CDC. CDC Estimates of 2009 H1N1 Influenza Cases, Hospitalizations and Deaths in the United States, April - October 17, 2009. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm.

  18. Obama Declares Swine Flu A National Emergency. The New York Times. October 24, 2009. Available at http://www.nytimes.com/reuters/2009/10/24/world/international-uk-flu-usa-obama.html.

  19. Domínguez-Cherit G, Lapinsky SE, Macias AE, Pinto R, Espinosa-Perez L, de la Torre A, et al. Critically Ill patients with 2009 influenza A(H1N1) in Mexico. JAMA. 2009 Nov 4. 302(17):1880-7. [Medline].

  20. Bautista E, Chotpitayasunondh T, Gao Z, Harper SA, Shaw M, Uyeki TM, et al. Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. N Engl J Med. 2010 May 6. 362(18):1708-19. [Medline]. [Full Text].

  21. Update: Influenza A (H3N2)v Transmission and Guidelines - Five States, 2011. MMWR Morb Mortal Wkly Rep. 2012 Jan 6. 60:1741-4. [Medline].

  22. Belongia EA, Irving SA, Waring SC, et al. Clinical characteristics and 30-day outcomes for influenza A 2009 (H1N1), 2008-2009 (H1N1), and 2007-2008 (H3N2) infections. JAMA. 2010 Sep 8. 304(10):1091-8. [Medline].

  23. Khandaker G, Zurynski Y, Buttery J, Marshall H, Richmond PC, Dale RC, et al. Neurologic complications of influenza A(H1N1)pdm09: Surveillance in 6 pediatric hospitals. Neurology. 2012 Oct 2. 79(14):1474-1481. [Medline].

  24. CDC. Guidance for Clinicians & Public Health Professionals. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/swineflu/guidance/. Accessed: April 27, 2009.

  25. National Center for Biotechnology Information. Influenza Virus Resource. Available at http://www.ncbi.nlm.nih.gov/genomes/FLU/SwineFlu.html. Accessed: May 4, 2009.

  26. NIAID. NIAID and 2009 H1N1 influenza. National Institute of Allergy and Infectious Diseases. Available at http://www.niaid.nih.gov/topics/flu/h1n1/research/Pages/researchProgram.aspx. Accessed: May 4, 2009.

  27. WHO guidelines for pharmacological management of pandemic (H1N1) 2009 influenza and other influenza viruses. World Health Organization. Available at http://www.who.int/csr/resources/publications/swineflu/h1n1_use_antivirals_20090820/en/index.html. Accessed: August 20, 2009.

  28. Graitcer SB, Gubareva L, Kamimoto L, et al. Characteristics of Patients with Oseltamivir-Resistant Pandemic (H1N1) 2009, United States. Emerg Infect Dis. 2011 Feb. 17(2):255-257. [Medline].

  29. Hernandez JE, Adiga R, Armstrong R, et al. Clinical experience in adults and children treated with intravenous peramivir for 2009 influenza A (H1N1) under an Emergency IND program in the United States. Clin Infect Dis. 2011 Mar. 52(6):695-706. [Medline]. [Full Text].

  30. CDC. Interim Guidance on Antiviral Recommendations for Patients with Confirmed or Suspected Swine Influenza A (H1N1) Virus Infection and Close Contacts. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/swineflu/recommendations.htm. Accessed: April 28, 2009.

  31. CDC. Update: drug susceptibility of swine-origin influenza A (H1N1) viruses, April 2009. MMWR Morb Mortal Wkly Rep. 2009 May 1. 58(16):433-5. [Medline]. [Full Text].

  32. Oseltamivir-resistant 2009 pandemic influenza A (H1N1) virus infection in two summer campers receiving prophylaxis--North Carolina, 2009. MMWR Morb Mortal Wkly Rep. 2009 Sep 11. 58(35):969-72. [Medline].

  33. Lee VJ, Yap J, Cook AR, Chen MI, Tay JK, Tan BH, et al. Oseltamivir ring prophylaxis for containment of 2009 H1N1 influenza outbreaks. N Engl J Med. 2010 Jun 10. 362(23):2166-74. [Medline].

  34. Maternal and Infant Outcomes Among Severely Ill Pregnant and Postpartum Women with 2009 Pandemic Influenza A (H1N1) --- United States, April 2009--August 2010. MMWR Morb Mortal Wkly Rep. 2011 Sep 9. 60:1193-6. [Medline]. [Full Text].

  35. CDC. Interim Guidance - Pregnant women and swine influenza: considerations for clinicians. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/swineflu/clinician_pregnant.htm. Accessed: April 29, 2009.

  36. Yin JK, Khandaker G, Rashid H, Heron L, Ridda I, Booy R. Immunogenicity and safety of pandemic influenza A (H1N1) 2009 vaccine: systematic review and meta-analysis. Influenza Other Respi Viruses. 2011 Mar 21. [Medline].

  37. US Food and Drug Administration. Influenza Virus Vaccine for the 2013-2014 Season. Available at http://www.fda.gov/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Post-MarketActivities/LotReleases/ucm343828.htm. Accessed: March 15, 2013.

  38. Jackson LA, Chen WH, Stapleton JT, Dekker CL, Wald A, Brady RC, et al. Immunogenicity and safety of varying dosages of a monovalent 2009 H1N1 influenza vaccine given with and without AS03 adjuvant system in healthy adults and older persons. J Infect Dis. 2012 Sep 15. 206(6):811-20. [Medline]. [Full Text].

  39. CDC 2009 H1N1 vaccination campaign planning checklist. August 31, 2009. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/H1N1flu/vaccination/statelocal/planning_checklist.htm. Accessed: September 1, 2009.

  40. CDC. Novel H1N1 vaccination recommendations. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/h1n1flu/vaccination/acip.htm. Accessed: September 1, 2009.

  41. Pasternak B, Svanström H, Mølgaard-Nielsen D, Krause TG, Emborg HD, Melbye M, et al. Vaccination against pandemic A/H1N1 2009 influenza in pregnancy and risk of fetal death: cohort study in Denmark. BMJ. 2012 May 2. 344:e2794. [Medline]. [Full Text].

  42. CDC. Interim Guidance for Infection Control for Care of Patients with Confirmed or Suspected Swine Influenza A (H1N1) Virus Infection in a Healthcare Setting. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/swineflu/guidelines_infection_control.htm. Accessed: April 29, 2009.

  43. Zhu FC, Wang H, Fang HH, Yang JG, Lin XJ, Liang XF, et al. A novel influenza A (H1N1) vaccine in various age groups. N Engl J Med. 2009 Dec 17. 361(25):2414-23. [Medline].

  44. US Food and Drug Administration. Letter from the Commissioner to Nation’s Health Care Professionals on H1N1 Vaccine Safety. Available at http://www.fda.gov/NewsEvents/PublicHealthFocus/ucm197733.htm. Accessed: January 14, 2010.

  45. Jain S, Benoit SR, Skarbinski J, Bramley AM, Finelli L. Influenza-Associated Pneumonia Among Hospitalized Patients With 2009 Pandemic Influenza A (H1N1) Virus--United States, 2009. Clin Infect Dis. 2012 May. 54(9):1221-1229. [Medline].

  46. Myles PR, Semple MG, Lim WS, Openshaw PJ, Gadd EM, Read RC, et al. Predictors of clinical outcome in a national hospitalised cohort across both waves of the influenza A/H1N1 pandemic 2009-2010 in the UK. Thorax. 2012 Mar 14. [Medline].

  47. CDC. Novel influenza A (H1N1) virus infections in three pregnant women - United States, April-May 2009. MMWR Morb Mortal Wkly Rep. 2009 May 15. 58(18):497-500. [Medline]. [Full Text].

  48. Jamieson DJ, Honein MA, Rasmussen SA, Williams JL, Swerdlow DL, Biggerstaff MS, et al. H1N1 2009 influenza virus infection during pregnancy in the USA. Lancet. 2009 Aug 8. 374(9688):451-8. [Medline].

  49. Siston AM, Rasmussen SA, Honein MA, Fry AM, Seib K, Callaghan WM, et al. Pandemic 2009 influenza A(H1N1) virus illness among pregnant women in the United States. JAMA. 2010 Apr 21. 303(15):1517-25. [Medline].

  50. Pierce M, Kurinczuk JJ, Spark P, Brocklehurst P, Knight M. Perinatal outcomes after maternal 2009/H1N1 infection: national cohort study. BMJ. 2011 Jun 14. 342:d3214. [Medline].

  51. CDC. Swine Flu: CDC Offers Clinical Guidance, WHO Raises Alert Level Again. Physician First Watch - Journal Watch. Available at http://firstwatch.jwatch.org/cgi/content/full/2009/430/1. Accessed: April 30, 2009.

  52. Hospitalized patients with novel influenza A (H1N1) virus infection - California, April-May, 2009. MMWR Morb Mortal Wkly Rep. 2009 May 22. 58(19):536-41. [Medline]. [Full Text].

  53. Kling J. Triple-Dose Flu Remedy Hastens H1N1 Viral Clearance. Medscape [serial online]. Available at http://www.medscape.com/viewarticle/811132. Accessed: September 24, 2013.

  54. Kumar A, ROSII Study Investigators. Viral Clearance with Standard or Triple Dose Oseltamivir Therapy in Critically Ill Patients with Pandemic (H1N1) 2009 Influenza. Abstract V-1470. Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). Available at http://www.icaaconline.com/php/icaac2013abstracts/data/papers/2013/V/2013_V-1470.htm. Accessed: September 24, 2013.

  55. WHO. Swine Influenza Frequently Asked Questions. World Health Organization. Available at http://www.who.int/csr/swine_flu/swine_flu_faq_26april.pdf. Accessed: April 27, 2009.

 
Previous
Next
 
This preliminary negative stained transmission electron micrograph depicts some of the ultrastructural morphology of the A/CA/4/09 swine flu virus. Courtesy of CDC/ C. S. Goldsmith and A. Balish.
Swine influenza virus. Colorized transmission electron micrograph (37,800X) of the A/New Jersey/76 (Hsw1N1) virus under plate magnification. Image taken during the virus' first developmental passage through a chicken egg. Courtesy of the CDC/Dr. E. Palmer; R.E. Bates.
Phase 6 criteria: In addition to the criteria defined in Phase 5, the same virus has caused sustained community-level outbreaks in at least one other country in another WHO region. Courtesy of the WHO.
Negative stained transmission electron micrograph of recreated 1918 influenza virions. Courtesy of CDC/ Dr. Terrence Tumpey.
This preliminary negative stained transmission electron micrograph depicts some of the ultrastructural morphology of the A/CA/4/09 swine flu virus. Courtesy of CDC/ C. S. Goldsmith and A. Balish.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.