Table 1.
Descriptive characteristics, univariate and multivariate associations between demographic and clinical characteristics and influenza-like illness during seasonal and A(H1N1)pdm09 influenza periods
| Influenza-like ilness (ILI) | ||||||||
|---|---|---|---|---|---|---|---|---|
| Seasonal influenza | A(H1N1)pdm09 influenza | |||||||
| Yes (N = 316) | No (N = 83 952) | Univariate | Multivariate | Yes (N = 167) | No (N = 84 291) | Univariate | Multivariate | |
| n (%) | n (%) | OR (95% CI) | OR (95% CI) | n (%) | n (%) | OR (95% CI) | OR (95% CI) | |
| Male gender | 133 (42·1) | 39 122 (46·6) | 0·83 (0·67–1·04) | 0·82 (0·66–1·02) | 79 (47·3) | 39 278 (46·6) | 1·03 (0·76–1·39) | 1·03 (0·76–1·40) |
| Age 18–39 yr | 117 (37·0) | 22 342 (26·6) | Reference | Reference | 86 (51·5) | 21 256 (25·2) | Reference | Reference |
| Age 40–59 yr | 130 (41·1) | 27 759 (33·1) | 0·89 (0·70–1·15) | 0·96 (0·74–1·24) | 56 (33·5) | 26 791 (31·8) | 0·52 (0·37–0·72) | 0·51 (0·36–0·72) |
| Age ⩾60 yr | 69 (21·8) | 33 851 (40·2) | 0·39 (0·29–0·52) | 0·48 (0·33–0·69) | 25 (15·0) | 36 244 (43·0) | 0·17 (0·11–0·27) | 0·19 (0·11–0·32) |
| Vaccination* | 78 (24·7) | 33 943 (40·4) | 0·48 (0·37–0·62) | 0·68 (0·51–0·92) | 43 (25·7) | 38 266 (45·4) | 0·42 (0·30–0·59) | 0·66 (0·42–1·04) |
| Respiratory diseases | 28 (8·9) | 11 469 (13·7) | 0·61 (0·42–0·91) | 0·73 (0·49–1·10) | 25 (15·0) | 12 905 (15·3) | 0·97 (0·64–1·49) | 1·24 (0·78–1·95) |
| Cardiovascular diseases | 55 (17·4) | 22 238 (26·5) | 0·59 (0·44–0·78) | 0·99 (0·69–1·40) | 25 (15·0) | 24 313 (28·8) | 0·43 (0·28–0·67) | 0·84 (0·50–1·42) |
| Other comorbidities† | 30 (9·5) | 10 424 (12·4) | 0·74 (0·51–1·08) | 1·12 (0·74–1·70) | 26 (15·6) | 11 717 (13·9) | 1·14 (0·75–1·74) | 2·43 (1·49–3·97) |
OR, Odds ratio; CI, confidence interval.
The percentages are the proportions of a given characteristic within ILI cases and non-cases.
*
To develop the model, seasonal vaccination status in 2008 was used; in applying the model at least one dose of A(H1N1)pdm09 influenza vaccine in 2009 was used.
†
Other comorbidities include diabetes mellitus, breathing problems due to neurological disorders, kidney failure, HIV, and other immunocompromising conditions.