OR of influenza-like illness in association with immunisation status
| Vaccines | Cases (244) | Controls (439) | Crude OR (CI 95%) | Adjusted* OR (CI 95%) |
| Any flu vaccines† | 41 | 27 | 3.1 (1.8 to 5.3) | 2.7 (1.6 to 4.7) |
| A-H1N1 vaccine | 13 | 12 | 2.2 (0.9 to 5.3) | 1.3 (0.6 to 3.1) |
| Seasonal vaccine | 27 | 18 | 3.0 (1.6 to 5.9) | 2.1 (1.1 to 4.1) |
| Not vaccinated | 203 | 412 | Reference | – |
Cases: all children hospitalised for ILI; controls: children hospitalised for thrombocytopaenia, gastroduodenal lesions, muco-cutaneous or neurological conditions; only children above 6 months of age are included.
↵* Adjusted by age and chronic diseases; the ORs of A-H1N1 and seasonal vaccine were also adjusted for the other influenza vaccine.
↵† In seven cases and two controls, the type of vaccine was not specified.