RT Journal Article SR Electronic(1) A1 Priest, P A1 Kelly, H YR 2015 T1 Influenza case definitions need to be fit for purpose JF Eurosurveillance VO 20 IS 25 SP 21162 OP DO https://doi.org/10.2807/1560-7917.ES2015.20.25.21162 UL https://www.eurosurveillance.org/content/10.2807/1560-7917.ES2015.20.25.21162