In the total vaccinated cohort , 62 children in the QIV group ( 2.40 % ) and 148 in the control group ( 5.73 % ) had rt-PCR-confirmed influenza , representing a QIV efficacy of 59.3 % ( 95 % confidence interval [ CI ] , 45.2 to 69.7 ) , with efficacy against culture-confirmed influenza of 59.1 % ( 97.5 % CI , 41.2 to 71.5 ) .