Table 3 Potential determinants for IVC for seasonal and pandemic influenza, 2009-2010 season

Age group

(Ref. Older than 64 years)

   0 - 4 years

0.03

(0.02-0.05)

0.3

(0.1-0.6)

< 0.001

1.8

(1.2-2.7)

2.1

(1.0-4.5)

0.04

   5 - 14 years

0.04

(0.03-0.07)

0.3

(0.2-0.6)

0.001

1.2

(0.8-2.0)

2.2

(1.0-4.8)

ns (0.05)

   15 - 29 years

0.05

(0.03-0.09)

0.4

(0.2-0.8)

0.005

0.6

(0.3-1.1)

1.3

(0.5-3.0)

Ns

   30 - 64 years

0.13

(0.1-0.2)

0.8

(0.5-1.2)

0.25

1.1

(0.8-1.6)

2.0

(1.0-3.8)

0.04

Number of children (< 5 years) in the household (ref. None)

   One child

0.2

(0.2-0.4)

0.8

(0.5 - 1.3)

ns

2.0

(1.4-2.9)

2.0

(1.3-3.1)

0.003

   Two children or more

0.3

(0.1-0.6)

0.8

(0.3 - 1.7)

ns

2.5

(1.4-4.4)

2.7

(1.4-5.1)

0.004

Number of persons in the household

(ref: 1 person)

   2 persons

0.8

(0.7-1.0)

0.9

(0.7 - 1.2)

ns

1.5

(1.0-2,1)

1.5

(1.0-2.2)

Ns

   3 persons

0.23

(0.2-0.3)

0.8

(0.5 - 1.1)

ns

2.0

(1.3-3.1)

3.5

(1.5-4.1)

< 0.001

   4 persons or more

0.2

(0.2-0.3)

0.8

(0.5 - 1.2)

ns

2.2

(1.5-3.2)

3.5

(1.4-4.3)

0.001

Gender

(Ref. female)

0.8

(0.7-1.0)

1.1

(0.9 - 1.4)

ns

1.2

(0.9-1.5)

1.1

(0.8-1.4)

Ns

Education level of the head of the family

(ref. primary level of education)

   Less than high school

0.3

(0.2-0.4)

0.7

(0.5 - 1.0)

ns

1.0

(0.7-1.5)

1.3

(0.8-2.0)

Ns

   High school graduate

0.3

(0.2 - 0.4)

0.7

(0.5 - 1.1)

ns

0.8

(0.4-1.3)

0.8

(0.4-1.4)

Ns

   University graduate (2 years)

0.1

(0.1-0.2)

0.4

(0.2 - 0.7)

< 0.001

1.3

(0.8-2.2)

1.5

(0.9-2.7)

Ns

   University graduate (>2 years)

0.3

(0.2-0.4)

0.9

(0.6 - 1.3)

ns

3.0

(2.0-4.4)

2.5

(1.5-4.1)

< 0.001

At-risk individual

(Ref. not to be an at-risk individual

   All age groups included

9.9

(7.7-12.2)

4.0

(2.6-6.0)

< 0.001

1.5

(1.0-2.3)

1.2

(0.7-2.0)

Ns

   At-risk individual younger than 65 years old

4.5

(3.1-6.6)

4.0

(2.6-6.1)

< 0.001

1.6

(1.0-2.5)

1.2

(0.7-2.0)

Ns

Healthcare worker*

4.2

(2.6-6.5)

4.9

(2.9-8.1)

< 0.001

4.4

(2.7-7.1)

3.0

(1.8-5.0)

0.001

Occupation of the head of the family

(Ref. manual worker)

   Farmer

0.6

(0.2-1.6)

0.7

(0.3-1.7)

ns

2.0

(0.8-5.4)

3.0

(1.1-8.0)

0.03

   Self employed

1.4

(0.8-2.5)

1.5

(0.8-2.6)

ns

2.3

(1.2-4.5)

1.9

(0.9-3.8)

Ns

   Higher professional and managerial occupation

0.9

(0.5-1.4)

0.9

(0.5-1.5)

ns

3.9

(2.4-6.2)

3.0

(1.5 - 5.5)

0.001

   Intermediate occupation

1.0

(0.6-1.6)

1.1

(0.6-1.9)

ns

2.2

(1.3-3.8)

2.0

(1.0-3.8)

0.04

   Clerical

0.7

(0.5-1.2)

0.8

(0.5-1.3)

ns

1.3

(0.8-2.1)

1.5

(0.8-2.6)

Ns

   Retired

6.9

(4.8-9.9)

1.7

(1.1-2.6)

0.02

2.2

(1.3-3.8)

2.0

(1.0-4.0)

0.04

   Student

0.4

(0.1-1.9)

0.4

(0.1-2.2)

ns

1.0

(0.2-4.7)

2.3

(0.4-13.0)

Ns

   Unemployed

3.1

(1.7-5.7)

1.9

(0.9-3.7)

ns

0.8

(0.3-2.0)

0.7

(0.2-1.9)

Ns

Town size

(Ref. rural)

   < 20,000 inhabitants

1.4

(1.0-1.8)

1.4

(1.0-1.9)

0.03

1.0

(0.7-1.5)

-

   [20,000; 100 000[ inhabitants

1.4

(1.0-1.9)

1.5

(1.1-2.2)

0.02

1.2

(0.7-1.8)

-

   ≥ 100 000 inhabitants

1.3

(1.0-1.6)

1.6

(1.2-2.2)

< 0.001

1.3

(0.9-1.9)

-

   Paris

0.9

(0.7-1.3)

1.2

(0.8-1.7)

ns

1.4

(0.9-2.2)

-

Free seasonal influenza vaccination offered (for non at-risk individuals)

3.9

(2.9-5.3)

4.5

(3.2-6.3)

< 0.001

-

-

Vaccinated against seasonal influenza

-

-

-

3.5

(2.7-4.6)

7.1

(5.1-10.0)

< 0.001