Table 3 Number of nosocomial influenza cases analyzed by Poisson regression

Unit^a

- Non-risk unit

1

–

–

- Risk unit

1.13

0.64–2.00

0.681

Epidemic season^b

- 2014–2015

1

–

–

- 2015–2016

1.17

0.63–2.16

0.619

- 2016–2017

0.96

0.55–1.67

0.881

- 2017–2018

1.18

0.70–2.00

0.540

- 2018–2019

1.52

0.91–2.56

0.111

Risk unit * epidemic season^c

- Risk unit * 2014–2015

1

–

–

- Risk unit * 2015–2016

0.56

0.23–1.34

0.191

- Risk unit * 2016–2017

0.39

0.19–0.81

0.011

- Risk unit * 2017–2018

0.50

0.24–1.03

0.060

- Risk unit * 2018–2019

0.48

0.23–0.97

0.042

Total number of influenza cases

1.07

1.06 – 1.07

< 0.0001