RT Journal Article SR Electronic(1) A1 Puig-Barberà, J YR 2011 T1 2010-2011 influenza seasonal vaccine, preliminary mid-season effectiveness estimates: reason for concern, confounding or are we following the right track? JF Eurosurveillance VO 16 IS 11 SP 19821 OP DO https://doi.org/10.2807/ese.16.11.19821-en UL https://www.eurosurveillance.org/content/10.2807/ese.16.11.19821-en