• 1
    World Health Organization. Global alert and response, pandemic (H1N1) 2009, frequently asked questions: what is phase 6? Available at (Accessed 8 October 2009).
  • 2
    Novel Swine-origin Influenza A (H1N1) Virus Investigation Team. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med2009; 360:26052615.
  • 3
    Garten RJ, Davis CT, Russell CA et al. Antigenic and genetic characteristics of swine-origin 2009 A (H1N1) influenza viruses circulating in humans. Science2009; 325:197201.
  • 4
    World Health organization. Pandemic (H1N1) 2009- UPDATE 94. Geneva: World Health organization, 2010. Available at (Accessed 9 April 2010).
  • 5
    Center for Disease Control and Prevention. Prevention and control of influenza: recommendations of the advisory Committee on Immunization Practices (ACIP), 2008. MMWR Recomm Rep2008; 57:160.
  • 6
    Thompson WW, Shay DK, Weintraub E et al. Influenza-associated hospitalizations in the United States. JAMA2004; 292:13331340.
  • 7
    Committee of the WHO Consultation on Clinical Aspects. Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. N Engl J Med2010; 362:17081719.
  • 8
    Baehr F, Morín G, Del Solar J, Olive H, Torres J. Clinical features of adults younger and older and than 50 years hospitalized with influenza A H1N1 2009 in a private hospital in Santiago, Chile. Rev Chilena Infectol2010; 27:139143.
  • 9
    National Institute of Statistics and Censuses. 2010. Available at: http:/ (Accessed 3 April 2011).
  • 10
    Centers for Disease Control and Prevention (CDC). CDC realtime RTPCR (rRTPCR) protocol for detection and characterization of influenza A (H1N1). Available at (Accessed 3 November 2009).
  • 11
    Fiore AE, Shay DK, Broder K et al. Prevention and control of seasonal influenza with vaccines: recommendations of the Advisory Committee on immunization Practices (ACIP), 2009. MMWR Recomm Rep2009; 58:152.
  • 12
    Jain S, Kaminoto L, Bramley AM et al. Hospitalized Patients with 2009 H1H1 Influenza in the United States, April–June 2009. N Engl J Med2009; 361:19351944.
  • 13
    Cui W, Zhao H, Lu X et al. Factors associated with death in hospitalized pneumonia patients with 2009 H1N1 influenza in Shenyang, China. BMC Infect Dis2010; 10:145.
  • 14
    Chowell G, Bertozzi S, Colchero MA et al. Severe respiratory disease concurrent with the circulation of H1N1 influenza. N Engl J Med2009; 361:674679.
  • 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. JAMA2009; 302:18961902.
  • 16
    Vaillant L, La Ruche G, Tarantola A, Barboza P. Epidemiology of fatal cases associated with pandemic H1N1 Influenza 2009. Euro Surveill2009; 14:pii: 19309.
  • 17
    Center for Disease Control and Prevention. Hospitalized Patients with Novel Influenza A (H1N1) Virus Infection –California, April–May, 2009. MMWR Morb Mortal Wkly Rep2009; 58:536541.
  • 18
    Center for Disease Control and Prevention. Deaths and hospitalizations related to 2009 pandemic influenza A (H1N1)- Greece, May 2009–February 2010. MMWR Morb Mortal Wkly Rep2010; 59:682686.
  • 19
    Center for Disease Control and Prevention. Intensive- care patients with severe novel influenza A (H1N1) virus infection- Michigan, June 2009. MMWR Morb Mortal Wkly Rep2009; 58:749752.
  • 20
    Karadeli E, Koç Z, Ulusan S, Erbay G, Demiroglu Y, Sen N. Chest radiography and CT finding in patients with the 2009 pandemic (H1N1) influenza. Diagn Interv Radiol2010; DOI 10.4261/1305-3825 DIR.3337-10.1.
  • 21
    Peralta Olalla P, Garcia M, Herrero MV et al. Risk factor for disease severity among hospitalised patients with 2009 pandemic influenza A (H1N1) in Spain, April–December 2009. Euro Surveill2010; 15:19.
  • 22
    Cao B, Li XW, Mao Y et al. Clinical features of the initial cases of 2009 pandemic influenza A(H1N1) virus infection in China. N Engl J Med2009; 361:25072517.
  • 23
    Kumar A, Zarychanski R, Pinto R et al. Critically ill patients with 2009 influenza A (H1N1) infection in Canada. JAMA2009; 302:18721879.
  • 24
    Kamigaki T, Oshitani H. Epidemiological characteristics and low case fatality rate of pandemic (H1N1) 2009 in Japan. PLoS Curr2009; 1:RRN1139.
  • 25
    Tamma P, Turnbull A, Rove S et al. Clinical outcomes of seasonal influenza and pandemic influenza A (H1N1) in pediatric in patients. BMC Pediatr2010; 10:72.
  • 26
    Winzer R, Kanig N, Schneitler S et al. Early clinical experiences with the new influenza A (H1N1/09). Dtsch Arztebl Int2009; 106:770776.
  • 27
    Libster R, Bugna J, Coviello S et al. Pediatric hospitalization associated with 2009 pandemic influenza A (H1N1) in Argentina. N Engl J Med2010; 362:4555.
  • 28
    Morgan O, Bramley A, Fowlkes A et al. Morbid obesity as a risk factor for hospitalization and death due to 2009 pandemic influenza A (H1N1) disease. PLoS ONE2010; 5:e9694 Doi 10.1371/journal.pone.0009694.
  • 29
    Siston A, Rasmussen S, Honei M et al. Pandemic 2009 influenza A (H1N1) virus illness among pregnant women in the United States. JAMA2010; 303:15171525.
  • 30
    Louie J, Acosta M, Jamieson D, Honein M. Severe 2009 H1N1 influenza in pregnant and postpartum women in California. N Engl J Med2010; 362:2735.
  • 31
    Dodds L, McNeil SA, Fell DB et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ2007; 176:463468.
  • 32
    Jamieson D, Honein M, Rasmussen S et al. H1N1 2009 influenza virus infection during pregnancy in the USA. Lancet2009; 374:451458.