Table 5.

H1N1 Case reports submitted to CISA with causal assessments of “possible” according to the modified WHO criteria

	Diagnosis	Number of case reports	Mean age (years)	Mean interval to symptom onset (days)	Vaccine type (TIVa, LAIVb, unknown)
GBS	Level 1c	11	51.5	17.7	7 TIV, 1 LAIV, 3 unknown
	Level 2c	30	53.2	11.9	27 TIV, 3 unknown
	Physician diagnosedd	2	17.5	13.0	1 LAIV, 1 unknown
Cranial neuropathy	Bell’s Palsy	4	38	9	2 TIV, 1 LAIV, 1 unknown
	Optic neuritis	1	46	14	TIV
	Sixth nerve palsy	1	15	13	TIV
Seizure	Prior history, febrile	2	14.5	4.5	TIV
	Prior history, afebrile	1	16	8	TIV
	No prior history, afebrile	3	2.0	5.3	1 TIV, 1 unknown
Other	ADEM	4	20.7	19.8	2 TIV, 1 LAIV, 1 unknown
	Transverse Myelitis	1	16	30	TIV
	Sensory neuropathy	3	42.0	6.7	2 TIV, 1 unknown
	Demyelinating disorders of unclear etiology	3	27	16.3	2 TIV, 1 LAIV
	Parasthesias	2	44.5	16.5	2 TIV
	Ataxia	1	2	22	LAIV
	Acute infarct of the basal ganglia	1	6	2	TIV
	Myasthenia gravis exacerbation	1	65	14	TIV
	Weakness, unclear etiology	1	37	1	TIV

^aTrivalent inactivated influenza vaccine,

^bLive-attenuated influenza vaccine,

^cBrighton Collaboration [10],

^dGBS diagnosed by neurologist, but did not meet Brighton Collaboration diagnostic criteria based on available data.