Healthcare workers had significantly more non-patient contacts at work (mean 14.3 versus 13.8, p = 0.021) but fewer contacts at home (mean 2.7 versus 3.5, P < 0.01) There were no significant differences in immunisation in the previous three seasons, or in household exposure to children. HCWs were significantly less likely to have a titer of <40 against A/California/07/2004, the A/ H3N2-strain of the previous season.