Reporting rate of the 10 most frequently reported potential immune-mediated diseases reported since launch until 18 May 2007 to 17 November 2011

Event system organ class	Event preferred term	Number of cases	Diagnostic certainty	Reporting rate per 100 000 doses distributed since launch
Nervous system disorders	VIIth nerve paralysis	19	Insufficient data: 5	0.066
			Alternative cause: 2
Nervous system disorders	Guillain–Barré syndrome	14	4 cases BC level 1–3	0.048
Skin and subcutaneous tissue disorders	Erythema multiforme	8	Insufficient data: 3	0.028
			Alternative cause: 1
Nervous system disorders	Optic neuritis	8	Insufficient data: 4	0.028
			Alternative cause: 1
Blood and lymphatic system disorders	Idiopathic thrombocytopenic purpura	7	Insufficient data: 1	0.024
			Alternative cause: 1
Musculoskeletal and connective tissue disorders	Systemic lupus erythematosus	7	Insufficient data: 2	0.024
			Alternative cause: 2
Nervous system disorders	Encephalitis	6	2 cases BC level 1–3	0.021
Nervous system disorders	Paralysis	6	*	0.021
Nervous system disorders	Multiple sclerosis	5	3 cases met criteria‡	0.017
Musculoskeletal and connective tissue disorders	Rheumatoid arthritis	5	Insufficient data: 2	0.017
			Alternative cause: 1

Insufficient data = information provided was insufficient to confirm the diagnosis.

Alternative cause = either other vaccines or drugs could have been implicated, or an alternative and biologically plausible cause was also suspected or reported.

BC = Brighton Collaboration definitions for Guillain–Barré syndrome¹⁷ and encephalitis³⁸ were level 1–3 (meets the case definition), level 4 (insufficient evidence to meet the case definition) and level 5 (diagnosis excluded).

^*Occurred in the context of other syndromes.

^†McDonald criteria for multiple sclerosis.³⁹