Table 4 Efficacy of influenza vaccination: titres ⩾40 to influenza.

	SLE patients (n = 56)	Healthy controls (n = 17)	p Value
A/H1N1 ⩾40 before vaccination	27 (48%)	1 (6%)	0.001
A/H1N1 ⩾40 after vaccination	47 (84%)	17 (100%)	0.105
A/H3N2 ⩾40 before vaccination	35 (63%)	7 (41%)	0.163
A/H3N2 ⩾40 after vaccination	48 (86%)	17 (100%)	0.185
B/Hong Kong ⩾40 before vaccination	14 (25%)	0 (0%)	0.030
B/Hong Kong ⩾40 after vaccination	39 (70%)	12 (71%)	1.000

Fisher's exact test was used for all variables.

SLE, systemic lupus erythematosus.