RT Journal Article SR Electronic(1) A1 Lyytikäinen, O A1 Nakari, U M A1 Lukinmaa, S A1 Kela, E A1 Nguyen Tran Minh, N A1 Siitonen, A YR T1 JF VO OP UL https://www.eurosurveillance.org/content/10.2807/esm.11.06.00630-fr