• 1
    Broberg E, Nicoll A, Amato-Gauci A. Seroprevalence to influenza A(H1N1) 2009 Virus–Where Are We? Clin Vaccine Immunol 2011; 18:12051212.
  • 2
    Kelly H, Peck HA, Laurie KL, Wu P, Nishiura H, Cowling BJ. The age-specific cumulative incidence of infection with pandemic influenza H1N1 2009 was similar in various countries prior to vaccination. PLoS ONE 2011; 6:e21828.
  • 3
    Roll U, Yaari R, Katriel G et al. Onset of a pandemic: characterizing the initial phase of the swine flu (H1N1) epidemic in Israel. BMC Infect Dis 2011; 11:92.
  • 4
    Bromberg M, Kaufman Z, Mandelboim M et al. Clinical and virological surveillance of influenza in Israel-implementation during pandemic influenza. Harefuah 2009; 148:577582, 659.
  • 5
    Engelhard D, Bromberg M, Averbuch D et al. Increased extent of and risk factors for pandemic (H1N1) 2009 and seasonal influenza among children, Israel. Emerg Infect Dis 2011; 17:17401743.
  • 6
    Kendal AP, Pereira MS, Skehel JJ. Concepts and Procedures for Laboratory-Based Influenza Surveillance. Atlanta, GA: US Department of Health and Human Services, CDC, 1982.
  • 7
    Rowe T, Abernathy RA, Hu-Primmer J et al. Detection of antibody to avian influenza A (H5N1) virus in human serum by using a combination of serologic assays. J Clin Microbiol 1999; 37:937943.
  • 8
    Zhu FC, Wang H, Fang HH et al. A novel influenza A (H1N1) vaccine in various age groups. N Engl J Med 2009; 361:24142423.
  • 9
    Hobson D, Curry RL, Bear AS, Ward-Gardner A. The role of serum haemagglutination-inhibiting antibody in protection against challenge infection with influenza A2 and B viruses. J Hyg (Lond) 1972; 70:767777.
  • 10
    de Jong JC, Palache AM, Beyer WE, Rimmelzwaan GF, Boon AC, Osterhaus AD. Haemagglutination-inhibiting antibody to influenza virus. Dev Biol (Basal) 2003; 115:6373.
  • 11
    Cox CM, Goodin K, Fisher E et al. Prevalence of 2009 pandemic influenza A (H1N1) virus antibodies, Tampa Bay Florida–November-December, 2009. PLoS ONE 2011; 6:e29301.
  • 12
    Israel Center for Disease control. Influenza activity weekly reports 2009–2010 in Israel. Available at, via internet (Accessed 6 February 2012).
  • 13
    Hancock K, Veguilla V, Lu X et al. Cross-reactive antibody responses to the 2009 pandemic H1N1 influenza virus. N Engl J Med 2009; 361:19451952.
  • 14
    Ikonen N, Strengell M, Kinnunen L et al. High frequency of cross-reacting antibodies against 2009 pandemic influenza A(H1N1) virus among the elderly in Finland. Euro Surveill 2010; 15:pii:19478.
  • 15
    Garten RJ, Davis CT, Russell CA et al. Antigenic and genetic characteristics of swine-origin 2009 A(H1N1) influenza viruses circulating in humans. Science 2009; 325:197201.
  • 16
    Itoh Y, Shinya K, Kiso M et al. In vitro and in vivo characterization of new swine-origin H1N1 influenza viruses. Nature 2009; 460:10211025.
  • 17
    Xu R, Ekiert DC, Krause JC, Hai R, Crowe JE Jr, Wilson IA. Structural basis of preexisting immunity to the 2009 H1N1 pandemic influenza virus. Science 2010; 328:357360.
  • 18
    Bandaranayake D, Huang QS, Bissielo A et al. Risk factors and immunity in a nationally representative population following the 2009 influenza A(H1N1) pandemic. PLoS ONE 2010; 5:e13211.
  • 19
    Burmaa A, Tsatsral S, Odagiri T, Suzuki A, Oshitani H, Nymadawa P. Cumulative incidence of pandemic influenza A (H1N1) 2009 by a community-based serological cohort study in Selenghe Province, Mongolia. Influenza Other Respi Viruses 2012; 6:e97e104.
  • 20
    Gilbert GL, Cretikos MA, Hueston L, Doukas G, O'Toole B, Dwyer DE. Influenza A (H1N1) 2009 antibodies in residents of New South Wales, Australia, after the first pandemic wave in the 2009 southern hemisphere winter. PLoS ONE 2010; 5:e12562.
  • 21
    Hardelid P, Andrews NJ, Hoschler K et al. Assessment of baseline age-specific antibody prevalence and incidence of infection to novel influenza A/H1N1 2009. Health Technol Assess 2010; 14:115192.
  • 22
    Miller E, Hoschler K, Hardelid P, Stanford E, Andrews N, Zambon M. Incidence of 2009 pandemic influenza A H1N1 infection in England: a cross-sectional serological study. Lancet 2010; 375:11001108.
  • 23
    Dellagi K, Rollot O, Temmam S et al. Pandemic influenza due to pH1N1/2009 virus: estimation of infection burden in Reunion Island through a prospective serosurvey, austral winter 2009. PLoS ONE 2011; 6:e25738.
  • 24
    Huo X, Qi X, Tang F et al. Seroprevalence of pandemic (H1N1) 2009 in pregnant women in China: an observational study. PLoS ONE 2011; 6:e17995.
  • 25
    Wang M, Yuan J, Li T et al. Antibody dynamics of 2009 influenza A (H1N1) virus in infected patients and vaccinated people in China. PLoS ONE 2011; 6:e16809.
  • 26
    Glass K, Kelly H, Mercer GN. Pandemic Influenza H1N1: reconciling serosurvey data with estimates of the reproduction number. Epidemiology 2012; 23:8694.