Skip to main content
    • Aa
    • Aa

Investigating the effect of high spring incidence of pandemic influenza A(H1N1) on early autumn incidence

  • H. BURKOM (a1), K. KNISS (a2), M. MELTZER (a3), L. BRAMMER (a2), Y. ELBERT (a1), L. FINELLI (a2) and D. SWERDLOW (a4)...

A pandemic H1N1 infection wave in the USA occurred during spring 2009. Some hypothesized that for regions affected by the spring wave, an autumn outbreak would be less likely or delayed compared to unaffected regions because of herd immunity. We investigated this hypothesis using the Outpatient Influenza-like Illness (ILI) Network, a collaboration among the Centers for Disease Control and Prevention, health departments, and care providers. We evaluated the likelihood of high early autumn incidence given high spring incidence in core-based statistical areas (CBSAs). Using a surrogate incidence measure based on influenza-related illness ratios, we calculated the odds of high early autumn incidence given high spring incidence. CBSAs with high spring ILI ratios proved more likely than unaffected CBSAs to have high early autumn ratios, suggesting that elevated spring illness did not protect against early autumn increases. These novel methods are applicable to planning and studies involving other infectious diseases.

Corresponding author
*Author for correspondence: Dr H. Burkom, Johns Hopkins Applied Physics Laboratory, National Security Technology Department, MS 8-224, 11100 Johns Hopkins Road, Laurel, MD 20723, USA. (Email:
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

1.JM Barry , C Viboud , L Simonsen . Cross-protection between successive waves of the 1918–1919 influenza pandemic: epidemiological evidence from US Army camps and from Britain. Journal of Infectious Diseases 2008; 198: 14271434.

7.B Woolf . On estimating the relation between blood group and disease. Annals of Human Genetics 1955; 19: 251253.

10.G Katriel , L Stone . 2010 Pandemic dynamics and the breakdown of herd immunity. PLoS ONE 5: e9565.

11.RB Couch , JA Kasel . Immunity to influenza in man. Annual Review of Microbiology 1983; 37: 529549.

12.V Andreasen , C Viboud , L Simonsen . Epidemiologic characterization of the 1918 influenza pandemic summer wave in Copenhagen: implications for pandemic control strategies. Journal of Infectious Diseases 2008; 197: 270278.

13.SS Shrestha , Estimating the burden of 2009 pandemic influenza A (H1N1) in the United States (April 2009–April 2010). Clinical Infectious Diseases 2011; 52: S75S82.

14.L Brammer , Surveillance for influenza during the 2009 influenza A (H1N1) pandemic – United States, April 2009–March 2010. Clinical Infectious Diseases 2011; 52: S27S35.

15.MA Jhung , Epidemiology of 2009 pandemic influenza A (H1N1) in the United States. Clinical Infectious Diseases 2011; 52: S13S26.

17.V Petrovic , Overview of the winter wave of 2009 pandemic influenza A(H1N1)v in Vojvodina, Serbia. Croatian Medical Journal 2011; 52: 141150.

19.H Nishiura , Pros and cons of estimating the reproduction number from early epidemic growth rate of influenza A (H1N1) 2009. Theoretical Biology and Medical Modelling 2010; 7: 1.

20.AS Monto , Clinical signs and symptoms predicting influenza Infection. Archives of Internal Medicine 2000; 160: 3243.

21.G Boivin , Predicting influenza infections during epidemics with use of a clinical case definition. Clinical Infectious Diseases 2000; 31: 1166.

22.T Smieszek , Reconstructing the 2003/2004 H3N2 influenza epidemic in Switzerland with a spatially explicit, individual-based model. BMC Infectious Diseases 2011; 11: 115.

23.RF Grais , JH Ellis , GE Glass . Assessing the impact of airline travel on the geographic spread of pandemic influenza. European Journal of Epidemiology 2003; 18: 10651072.

24.JS Brownstein , CJ Wolfe , KD Mandl . Empirical evidence for the effect of airline travel on inter-regional influenza spread in the United States. PLoS Medicine 2006; 3: e401.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Epidemiology & Infection
  • ISSN: 0950-2688
  • EISSN: 1469-4409
  • URL: /core/journals/epidemiology-and-infection
Please enter your name
Please enter a valid email address
Who would you like to send this to? *