Table 3.

Seasonal influenza vaccination histories of live poultry vendors, poultry farmers and non-poultry workers based on the serological test results

Virus antigen	Antibody titre*	Seasonal influenza vaccination history in past 2 years
		Live poultry vendors (N = 335)			Poultry farmers (N = 335)			Non-poultry workers (N = 577)
		2010	2011	None	2010	2011	None	2010	2011	None
H5N2	<1:10	1	1	4	4	4	6	21	20	8
	1:10	6	5	16	15	12	20	61	60	32
	1:20	40	36	124	72	62	93	152	145	125
	1:40	20	20	102	33	27	76	73	66	70
	1:80	2	2	8	4	2	2	0	0	2
H7N3	<1:10	64	59	231	123	104	185	293	280	225
	1:10	2	2	14	4	2	5	9	6	10
	1:20	2	2	8	0	0	4	5	5	1
	1:40	1	1	1	1	1	3	0	0	1
H7N9	<1:10	69	64	254	128	107	197	307	291	237
	1:10	0	0	0	0	0	0	0	0	0
H6N1	<1:10	69	64	254	128	107	196	307	291	237
	1:10	0	0	0	0	0	0	0	0	0
	1:20	0	0	0	0	0	0	0	0	0
	1:40	0	0	0	0	0	1	0	0	0

^*The cut-off antibody titre (bold font) of seropositivity was 1:80 for H5N2 and 1:40 for H7N3, H7N9 and H6N1 viruses.