Estimates of the reproduction number for seasonal, pandemic, and zoonotic influenza: a systematic review of the literature

Details

• Alternative Title:
  BMC Infect Dis
• Personal Author:
  Biggerstaff, Matthew ; Cauchemez, Simon ; Reed, Carrie ; Gambhir, Manoj ; Finelli, Lyn
• Description:
  Background
  
  The potential impact of an influenza pandemic can be assessed by calculating a set of transmissibility parameters, the most important being the reproduction number (R), which is defined as the average number of secondary cases generated per typical infectious case.
  
  Methods
  
  We conducted a systematic review to summarize published estimates of R for pandemic or seasonal influenza and for novel influenza viruses (e.g. H5N1). We retained and summarized papers that estimated R for pandemic or seasonal influenza or for human infections with novel influenza viruses.
  
  Results
  
  The search yielded 567 papers. Ninety-one papers were retained, and an additional twenty papers were identified from the references of the retained papers. Twenty-four studies reported 51 R values for the 1918 pandemic. The median R value for 1918 was 1.80 (interquartile range [IQR]: 1.47–2.27). Six studies reported seven 1957 pandemic R values. The median R value for 1957 was 1.65 (IQR: 1.53–1.70). Four studies reported seven 1968 pandemic R values. The median R value for 1968 was 1.80 (IQR: 1.56–1.85). Fifty-seven studies reported 78 2009 pandemic R values. The median R value for 2009 was 1.46 (IQR: 1.30–1.70) and was similar across the two waves of illness: 1.46 for the first wave and 1.48 for the second wave. Twenty-four studies reported 47 seasonal epidemic R values. The median R value for seasonal influenza was 1.28 (IQR: 1.19–1.37). Four studies reported six novel influenza R values. Four out of six R values were <1.
  
  Conclusions
  
  These R values represent the difference between epidemics that are controllable and cause moderate illness and those causing a significant number of illnesses and requiring intensive mitigation strategies to control. Continued monitoring of R during seasonal and novel influenza outbreaks is needed to document its variation before the next pandemic.
  
  Electronic supplementary material
  
  The online version of this article (doi:10.1186/1471-2334-14-480) contains supplementary material, which is available to authorized users.
  
  
• Subjects:
  Animals Humans Influenza, Human Influenza A Virus Seasons Zoonoses
• Source:
  BMC Infect Dis. 14.
• Document Type:
  Journal Article
• Funding:
  U54 GM088491/GM/NIGMS NIH HHS/United States
• Volume:
  14
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:aa373c6972df7b802e83c76c7b6ad8795b85b5f8d91cfc881a75463ae0086982
• Download URL:
  https://stacks.cdc.gov/view/cdc/25291/cdc_25291_DS1.pdf
• File Type:
  [PDF - 1.45 MB ]