Pooled crude and adjusted Influenza vaccine effectiveness against influenza A(H3N2) in target group for vaccination swabbed less than five days after ILI symptoms onset (N = 1058), by age group, EU, 2011–12.

*Adjusted for study site and week of onset.aAdjusted for study site, week of symptoms onset, age group (four categories), gender, GP visit in the previous three months, hospitalisation in the previous year, presence of chronic condition, presence of lung diseases and presence of cardiovascular disease.bAdjusted for study site, week of symptoms onset, gender, GP visit in the previous three months, hospitalisation in the previous year, presence of chronic condition, presence of lung diseases and presence of cardiovascular disease. 24 controls dropped due to no cases in this age group, targeted by the vaccination, on the 7th pair of weeks.¥16 controls dropped due to no cases in this age group on the 7th pair of weeks. 1 control dropped due to no cases in Italy.±1 control dropped due to no cases in Italy.Ω17 controls dropped due to no cases in this age group on the 7th pair of weeks. 1 case dropped due to no controls in Italy.