Table 5. Comparison of the influenza vaccination status of inpatient vs outpatient influenza cases by influenza (sub)type, age group and season, northern Spain, 2010/11 to 2015/16.

	Inpatient cases		Outpatient cases		AOR (95% CI)a	p value
All ages and seasons	n	% vaccinated	n	% vaccinated
Total	685	49	557	26	0.83 (0.59 to 1.18)	0.304
Influenza A(H1N1)pdm09	304	40	196	22	0.73 (0.42 to 1.27)	0.268
Influenza A(H3N2)	246	57	228	33	0.46 (0.24 to 0.90)	0.023
Influenza B	130	52	134	21	1.64 (0.75 to 3.59)	0.215
Age 50–64 years
Total	188	21	384	13	1.03 (0.59 to 1.80)	0.919
Influenza A(H1N1)pdm09	125	19	148	12	1.17 (0.53 to 2.58)	0.698
Influenza A(H3N2)	37	24	138	15	0.32 (0.09 to 1.23)	0.099
Influenza B	26	23	98	12	2.36 (0.59 to 9.45)	0.227
Age ≥ 65 years
Total	497	59	173	55	0.71 (0.44 to 1.14)	0.156
Influenza A(H1N1)pdm09	179	55	48	56	0.41 (0.16 to 1.03)	0.056
Influenza A(H3N2)	209	63	90	59	0.50 (0.22 to 1.12)	0.092
Influenza B	104	59	36	44	1.81 (0.63 to 5.17)	0.269
Influenza season
2010/11	50	40	50	14	3.03 (0.83 to 11.12)	0.095
2011/12	17	47	112	26	0.40 (0.09 to 1.88)	0.245
2012/13	24	33	66	14	1.17 (0.15 to 8.95)	0.877
2013/14	186	49	93	38	0.49 (0.24 to 0.99)	0.048
2014/15	165	58	114	32	0.91 (0.45 to 1.83)	0.797
2015/16	243	46	122	24	0.87 (0.45 to 1.67)	0.668

AOR: adjusted odds ratio; CI: confidence interval.

^a OR and 95% CI adjusted by age groups (50–59, 60–69, 70–79 and ≥ 80 years), sex, major chronic conditions, functional dependence, hospitalisation in the previous 12 months, and influenza season and month of sample collection.