Table 1. Distribution according to influenza season of number of samples with available information and percentage of vaccinated cases. Catalonia, 2010–2013.

Season	Number of samples with immunization record	Number of samples with no immunization record	OR (95%CI) P value
2010–2011	1117	154 (12.1%)	0.83(0.64–1.07) 0.16
2011–2012	1092	125 (10.3%)	ref
2012–2013	964	157 (14%)	0.70(0.54–0.91) 0.006

OR, odds ratio; CI, confidence interval.