Table 3.
Vaccination status and prevalence of underlying medical conditions conferring a higher risk of influenza related complications, by age group
| Characteristics by age group | No (%) cases | No (%) controls | Crude odds ratio (95% CI)* | P value | Adjusted odds ratio (95% CI)† | P value |
|---|---|---|---|---|---|---|
| <5 years (10 cases, 30 controls) | ||||||
| Vaccinated | 4 (40.0) | 16 (53.3) | 0.59 (0.14 to 2.49) | 0.5 | 0.4 (0.06 to 3.10) | 0.4 |
| Underlying conditions‡: | 2 (20.0) | 26 (86.7) | 0.05 (0.01 to 0.29) | 0.001 | — | — |
| Asthma | 1 (10.0) | 13 (43.3) | 0.16 (0.02 to 1.36) | 0.09 | — | — |
| Obstructive sleep apnoea | 1 (10.0) | 10 (33.3) | 0.23 (0.03 to 2.05) | 0.2 | — | — |
| Gastro-oesophageal reflux | 0 | 4 (13.3) | — | 0.6§ | — | — |
| Interstitial pneumopathy | 0 | 1 (3.3) | — | 1§ | — | — |
| Chronic heart disease | 0 | 1 (3.3) | — | 1§ | — | — |
| 5-20 years (7 cases, 21 controls) | ||||||
| Vaccinated | 1 (14.3) | 3 (14.3) | 1 (0.08 to 12.85) | 1 | 0.5 (0.02 to 10.95) | 0.7 |
| Underlying conditions*: | 2 (28.6) | 15 (71.4) | 0.19 (0.03 to 1.13) | 0.07 | — | — |
| Asthma | 1 (14.3) | 14 (66.7) | 0.1 (0.01 to 0.92) | 0.04 | — | — |
| Chronic heart disease | 0 | 1 (4.8) | — | 1§ | — | — |
| Chronic renal insufficiency | 1 (14.3) | 0 | — | 0.3§ | — | — |
| Other | 0 | 1 (4.8) | — | 1§ | — | — |
| 21-40 years (18 cases, 54 controls) | ||||||
| Vaccinated | 1 (5.6) | 12 (22.2) | 0.21 (0.03 to 1.73) | 0.1 | 0.25 (0.03 to 2.19) | 0.2 |
| Underlying conditions*: | 6 (33.3) | 31 (57.4) | 0.37 (0.12 to 1.15) | 0.1 | — | — |
| Asthma | 0 | 14 (25.9) | — | 0.02§ | — | — |
| Obstructive sleep apnoea | 0 | 5 (9.3) | — | 0.3§ | — | — |
| Chronic obstructive pulmonary disease | 0 | 1 (1.9) | — | 1§ | — | — |
| Diabetes | 4 (22.2) | 0 | — | 0.003§ | — | — |
| Gastro-oesophageal reflux | 0 | 3 (5.6) | — | 0.6§ | — | — |
| HIV/AIDS | 1 (5.6) | 8 (14.8) | 0.35 (0.04 to 2.93) | 0.3 | — | — |
| Interstitial pneumopathy | 0 | 1 (1.9) | — | 1§ | — | — |
| Obesity | 2 (11.1) | 2 (3.7) | 3.32 (0.42 to 26.16) | 0.3 | — | — |
| Lung cancer | 0 | 1 (1.9) | — | 1§ | — | — |
| Chronic renal insufficiency | 1 (5.6) | 0 | — | 0.3§ | — | — |
| Other | 1 (5.6) | 6 (11.1) | 0.48 (0.05 to 4.18) | 0.5 | — | — |
| 41-60 years (20 cases, 60 controls) | ||||||
| Vaccinated | 1 (5.0) | 18 (30.0) | 0.13 (0.01 to 1.00) | 0.05 | 0.05 (0.006 to 0.53) | 0.01 |
| Underlying conditions*: | 4 (20.0) | 36 (60.0) | 0.17 (0.05 to 0.57) | 0.004 | — | — |
| Asthma | 0 | 10 (16.7) | — | 0.06§ | — | — |
| Obstructive sleep apnoea | 1 (5.0) | 5 (8.3) | 0.59 (0.065 to 5.23) | 0.6 | — | — |
| Chronic obstructive pulmonary disease | 1 (5.0) | 8 (13.3) | 0.35 (0.04 to 2.92) | 0.3 | — | — |
| Diabetes | 3 (15.0) | 5 (8.3) | 1.92 (0.42 to 8.77) | 0.4 | — | — |
| Gastro-oesophageal reflux | 0 | 3 (5.0) | — | 0.6§ | — | — |
| HIV/AIDS | 0 | 2 (3.3) | — | 1§ | — | — |
| Interstitial pneumopathy | 0 | 3 (5.0) | — | 0.6§ | — | — |
| Obesity | 0 | 2 (3.3) | — | 1§ | — | — |
| Lung cancer | 0 | 3 (5.0) | — | 0.6§ | — | — |
| Chronic heart disease | 0 | 2 (3.3) | — | 1§ | — | — |
| Chronic renal insufficiency | 0 | 1 (1.7) | — | 1§ | — | — |
| Other | 0 | 5 (8.3) | — | 0.3§ | — | — |
| >60 years (5 cases, 15 controls) | ||||||
| Vaccinated | 1 (20.0) | 4 (26.7) | 0.65 (0.05 to 8.97) | 0.7 | 0.37 (0.01 to 11.64) | 0.6 |
| Underlying conditions*: | 1 (20.0) | 12 (80.0) | 0.08 (0.01 to 0.87) | 0.04 | — | — |
| Obstructive sleep apnoea | 0 | 2 (13.3) | — | 1§ | — | — |
| Chronic obstructive pulmonary disease | 0 | 7 (46.7) | — | 0.1§ | — | — |
| Diabetes | 0 | 1 (6.7) | — | 1§ | — | — |
| Gastro-oesophageal reflux | 0 | 1 (6.7) | — | 1§ | — | — |
| Interstitial pneumopathy | 0 | 2 (13.3) | — | 1§ | — | — |
| Lung cancer | 0 | 1 (6.7) | — | 1§ | — | — |
| Chronic renal insufficiency | 0 | 1 (6.7) | — | 1§ | — | — |
| Other | 1 (20.0) | 1 (6.7) | 3.46 (0.18 to 67.64) | 0.4 | — | — |
*Calculated using conditional logistic regression.
†Conditional logistic regression used to control for sex and underlying medical conditions conferring a higher risk for influenza complications.
‡Medical conditions conferring a higher risk of influenza related complications.
§Fisher’s exact test.