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Table 2 Comparison of reproduction number estimates for the A/H7N9 influenza viruses, other emerging zoonoses with pandemic potential, and human influenza viruses

From: Transmission potential of influenza A/H7N9, February to May 2013, China

Outbreak R estimate Source and method
A/H7N9 outbreak   
Avian influenza A/H7N9- 2013, China 0.1 (95% CrI: 0.01 to 0.49) This study; Bayesian approach from [11]
Avian influenza A/H7N9- 2013, China 0.03 to 0.05 This study; exposure-based approach from [20]
Avian influenza A/H7N9- 2013, China 0.28 (95% CI: 0.11 to 0.45) Analysis of cluster size distribution from [22]
Other zoonotic influenza viruses
Avian influenza H5N1 -2003 to 2006, SE Asia and Egypt/Turkey 0.29 Cluster size distribution approach [21]; data from [29]
Avian influenza H5N1 – 2004 to 2006; SE Asia and Egypt/Turkey 0.52 to 0.54 [11] Bayesian approach
Swine influenza H3N2v - 2011, USA 0.5 to 0.74 Exposure-based approach [20]; data from [30]
Human influenza viruses
1918 A/H1N1 influenza pandemic 1.8 to 5.4 [16, 18, 31, 32] Various approaches
1957 A/H2N2 influenza pandemic 1.5 [33] growth rate
1968 A/H3N2 influenza pandemic 1.5 [33] growth rate
2009 A/H1N1 influenza pandemic 1.2 to 3.1 [17, 3440] Various approaches
Seasonal influenza 1.3 [41, 42] growth rate
Other zoonotic viruses
Nipah virus, Malaysia, 1990s 0.05 to 0.08 Exposure-based approach [20]; data from [43]
Nipah virus, Bangladesh, 2000s 0.48 to 0.51 Exposure-based and cluster size distribution approaches [20]; to data from [21]
SARS virus, Singapore, Hong Kong, 2003 2.2 to 3.6 [15, 44] Epidemic model fitted to case series during the pre-intervention period
  1. SARS, severe acute respiratory syndrome.