Table 2.
Cases and controlsa characteristics and vaccination history by group: overall, high-risk conditions, and 60 years old or older.
| Overall | Cases N = 102 % |
Controls N = 116 % |
P value |
|---|---|---|---|
| Age ≥ 65 | 42.2 | 80.2 | <0.0001 |
| Age group | |||
| 18–49 | 24.5 | 4.3 | <0.0001 |
| 50–64 | 33.3 | 15.5 | |
| 65–74 | 13.7 | 25.0 | |
| ≥75 | 28.4 | 55.2 | |
| Male | 55.9 | 49.1 | 0.3200 |
| High risk conditionsb | |||
| None | 22.6 | 10.3 | 0.0360 |
| One | 31.4 | 31.0 | |
| Two or more | 46.1 | 58.6 | |
| GP consultations | |||
| None | 25.5 | 19.0 | 0.0110 |
| One | 34.3 | 20.7 | |
| Two or more | 40.2 | 60.3 | |
| Hospitalized last 12 months | 27.5 | 43.1 | 0.0160 |
| Barthel index (over 136 subjects 65 years old or older) | N = 43 | N = 93 | |
| <20 Total | 2.3 | 0 | 0.1600 |
| 20–35 Severe | 0 | 1.1 | |
| 40–55 Moderate | 4.7 | 14.0 | |
| ≥60 Mild | 93.2 | 85.0 | |
| Social classc | |||
| I-III N | 25.9 | 11.2 | 0.0230 |
| III-M | 12.8 | 14.7 | |
| IV-V | 61.4 | 73.9 | |
| Never smoker | 42.2 | 56.9 | 0.0300 |
| Contact with children | 38.2 | 33.6 | 0.4780 |
| ICU admission | 5.9 | 1.7 | 0.1510 |
| Death | 2.0 | 4.3 | 0.4520 |
| Length of stay mean (SE) | 0.45 | 0.44 | 0.4303 |
| Vaccine | |||
| 23-valent Pneumococcal | 12.8 | 25.9 | 0.0150 |
| Influenza seasonal 2009 | 35.3 | 64.7 | <0.0001 |
| Influenza pandemic | 21.6 | 30.2 | 0.0162 |
| Influenza seasonal 2010d | 36.3 | 66.4 | <0.0001 |
| High-risk conditions | N = 79% | N = 104% | |
|---|---|---|---|
| Age group | |||
| 18–49 | 16.5 | 2.9 | <0.0001 |
| 50–64 | 36.7 | 14.4 | |
| 65–74 | 13.9 | 25.0 | |
| ≥75 | 32.9 | 57.7 | |
| High risk conditionsb | |||
| At least one | 40.5 | 34.6 | 0.4140 |
| Two or more | 59.5 | 65.4 | |
| Visits to GP | |||
| None | 29.1 | 18.3 | 0.0790 |
| One | 26.6 | 21.2 | |
| Two or more | 44.3 | 60.6 | |
| Vaccines administered | |||
| 23-valent Pneumococcal | 16.5 | 28.9 | 0.0500 |
| Influenza seasonal 2009 | 40.5 | 66.4 | <0.0001 |
| Influenza pandemic | 27.9 | 33.7 | 0.4010 |
| Influenza seasonal 2010d | 41.8 | 68.3 | <0.0001 |
| 60 years old or older | N = 58% | N = 103% | |
|---|---|---|---|
| Age group | |||
| 60–64 | 25.9 | 9.7 | 0.0250 |
| 65–74 | 24.2 | 28.2 | |
| ≥75 | 50 | 62.1 | |
| High risk conditions b | |||
| None | 12.7 | 6.8 | 0.5070 |
| At least one | 27.6 | 31.1 | |
| Two or more | 60.3 | 62.1 | |
| Visits to GP | |||
| None | 20.7 | 18.5 | 0.2180 |
| One | 34.5 | 23.3 | |
| Two or more | 44.8 | 58.3 | |
| Vaccines administered | |||
| 23-valent Pneumococcal | 19.0 | 29.1 | 0.1550 |
| Influenza seasonal 2009 | 51.7 | 70.9 | 0.0150 |
| Influenza pandemic | 29.3 | 31.2 | 0.8160 |
| Influenza seasonal 2010d | 51.7 | 72.8 | 0.0007 |
GP: General practitioner, ICU: intensive care unit, Barthel Index: index of functional daily life activities, SE: standard error.
Cases (influenza positive) and controls (positive for other than influenza respiratory virus).
High-risk conditions: cardiovascular disease, chronic pulmonary disease, chronic hepatic disease, chronic renal disease, diabetes mellitus, neuromuscular disorders, neoplasm, immunodeficiency or immunosuppressive therapies, obesity (body mass index, 40 and over).
I: Professional, II: Managerial and technical, III: Skilled: (N) Non-manual, (M) Manual, IV: Partly skilled, V: Unskilled.
Vaccinated 14 or more days before symptoms onset.