Table 1.

Definition of the adverse events potentially associated with influenza vaccines

Adverse events potentially associated with influenza vaccines	ICD-9-CM	Risk period (days after the vaccination)
Bell’s palsy	351.0	60
Acute hepatitis	570; 572.2; 573.3; 573.9	60
Guillain-Barré syndrome	357.0; 357.8; 357.9	42
Encephalitis and encephalomyelitis	323; 348.3	42
Thrombocytopaenia	283.0; 286.5; 287 (excl. 287.39); V83.01; V83.02	42
Vasculitis	136.1; 273.2; 287.0; 446.0; 446.2; 446.4; 446.5; 446.6; 446.7; 709.1	42
Demyelinating diseases	323.81; 340; 341.0; 341.1; 341.2; 341.9; 377.3; 377.49; 377.9; 725	42
Convulsions	780.39	14
Anaphylaxis	995.0; 999.4	2
Neuritis (brachial neuritis, neuralgic amyotrophy)	353.5; 723.4	28
Narcolepsy	347	42
Swelling of limb	729.81	–
Syncope and collapse	780.2	–

ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification.