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Table 1 Reproduction numbers from the 1918 Influenza A/H1N1 Pandemic

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

Location

Wavea

Study population

Mean GT/SIb

Reproduction Number (R)

95% CIc

Basic or effective

Case definition

Reference

Year published

Australia

1st

Community

2.6

1.80

1.6–2.0

Basic

Unconfirmed hospitalizations/deaths

[15]

2008

Brazil

1st

Community

4

2.68

 

Basic

Unconfirmed illness

[16]

2007

Canada

1st

Community

3

1.50

1.5–1.5

Basic

Unconfirmed deaths

[17]

2011

Canada

1st

Community

6

2.1

2.1–2.1

Basic

Unconfirmed deaths

[17]

2011

Colombia

1st

Community

3

1.4–1.5

 

Effective

Unconfirmed deaths

[18]

2012

Colombia

1st

Community

4

1.5–1.7

 

Effective

Unconfirmed deaths

[18]

2012

Denmark

1st

Community

2.6

2.2–2.4

 

Effective

Unconfirmed illness

[19]

2008

Denmark

1st

Community

4

2.8–3.0

 

Effective

Unconfirmed illness

[19]

2008

Denmark

1st

Community

2.6

2.8–4.0

 

Effective

Unconfirmed hospitalizations

[19]

2008

Denmark

1st

Community

4

3.6–5.4

 

Effective

Unconfirmed hospitalizations

[19]

2008

Italy

1st

Community

3

1.03

1.00–1.08

Basic

Unconfirmed hospitalizations

[20]

2011

Mexico

1st

Community

3

1.30

 

Effective

Unconfirmed deaths

[21]

2010

Peru

1st

Community

3

1.38

1.37–1.40

Effective

Unconfirmed deaths

[22]

2011

Switzerland

1st

Community

3.11

1.49

1.45–1.53

Basic

Unconfirmed hospitalizations

[23]

2006

Switzerland

1st

Community

3.4

1.50

 

Basic

Unconfirmed deaths

[24]

2009

United Kingdom

1st

Community

2.6

1.7

 

Basic

Unconfirmed deaths

[10]

2006

United Kingdom

1st

Community

4.1

2.10

 

Effective

Unconfirmed illness

[25]

2006

United Kingdom

1st

Community

6

2.00

 

Basic

Unconfirmed illness

[26]

2005

United Kingdom

1st

Community

NR

1.16–2.94

 

Effective

Unconfirmed illness

[27]

2010

United Kingdom

1st

Students

NR

1.43–5.36

 

Effective

Unconfirmed illness

[27]

2010

USA

1st

Community

4

1.34–3.21

 

Effective

Unconfirmed illness

[28]

2008

Various

1st

Community

4

1.2–3.0

 

Effective

Unconfirmed illness

[29]

2007

Various

1st

Community

4

2.1–7.5

 

Effective

Unconfirmed illness

[29]

2007

 

1st

Sailors

4

4.97

 

Effective

Unconfirmed illness

[28]

2008

Canada

2nd

Community

3.6

2.26

1.95–2.63

Basic

Unconfirmed illness

[30]

2010

Canada

2nd

Community

3.6

1.49

1.42–1.55

Basic

Unconfirmed illness

[30]

2010

Canada

2nd

Community

3

2.40

2.4–2.5

Basic

Unconfirmed deaths

[17]

2011

Canada

2nd

Community

6

4.3

4.2–4.4

Basic

Unconfirmed deaths

[17]

2011

Denmark

2nd

Community

2.6

1.22–1.24

 

Effective

Unconfirmed illness

[19]

2008

Denmark

2nd

Community

4

1.29–1.33

 

Effective

Unconfirmed illness

[19]

2008

Denmark

2nd

Community

2.6

1.2–1.3

 

Effective

Unconfirmed hospitalizations

[19]

2008

Denmark

2nd

Community

4

1.3–1.4

 

Effective

Unconfirmed hospitalizations

[19]

2008

Germany

2nd

Community

1

1.58

0.03–10.3

Basic

Unconfirmed deaths

[31]

2007

Germany

2nd

Community

3

2.52

0.75–5.85

Basic

Unconfirmed deaths

[31]

2007

Germany

2nd

Community

5

3.41

1.91–5.57

Basic

Unconfirmed deaths

[31]

2007

Italy

2nd

Community

3

1.38

1.3–1.5

Basic

Unconfirmed hospitalizations

[20]

2011

Mexico

2nd

Community

3

1.30

 

Effective

Unconfirmed deaths

[21]

2010

New Zealand

2nd

Military

>1.5

1.3–3.1

 

Basic

Unconfirmed hospitalizations

[32]

2006

Switzerland

2nd

Community

2.28

3.75

3.6–3.9

Effective

Unconfirmed hospitalizations

[23]

2006

Switzerland

2nd

Community

3.4

2.40

 

Basic

Unconfirmed deaths

[24]

2009

United Kingdom

2nd

Community

3

1.39

1.36–1.43

Effective

Unconfirmed deaths

[33]

2008

United Kingdom

2nd

Community

6

1.84

1.75–1.92

Effective

Unconfirmed deaths

[33]

2008

United Kingdom

2nd

Community

6

1.55

 

Basic

Unconfirmed illness

[26]

2005

United Kingdom

2nd

Community

2.6

1.50

 

Basic

Unconfirmed deaths

[10]

2006

USA

2nd

Community

2.5

2.14

 

Basic

Unconfirmed deaths

[34]

2009

USA

2nd

Community

NR

2.20

1.55–2.84

Effective

Unconfirmed illness

[35]

2007

USA

2nd

Community

4

2.00

1.7–2.3

Effective

Unconfirmed deaths

[36]

2004

USA

2nd

Community

2.85

1.73

 

Effective

Unconfirmed deaths

[14]

2007

United Kingdom

3rd

Community

3

1.39

1.29–1.49

Effective

Unconfirmed deaths

[33]

2008

United Kingdom

3rd

Community

6

1.82

1.61–2.05

Effective

Unconfirmed deaths

[33]

2008

United Kingdom

3rd

Community

6

1.70

 

Basic

Unconfirmed illness

[26]

2005

Median reproduction number for the 1918 pandemic: 1.80; Interquartile range 1.47–2.27

  1. aThe first wave of illnesses began in the Northern Hemisphere in the spring 1918 [1]. A second wave of more intense transmission occurred concurrently in North America, Europe, and Africa in the Fall of 1918 while a third and final wave of activity occurred in some areas of the world during the winter of 1919 [37].
  2. bThe generation time (GT) or serial interval (SI) assumed in the reproduction number estimation.
  3. cConfidence interval.
  4. NR = Not reported.
  5. This table is also available as a .csv file as Additional file 1.