Prevailing effectiveness of the 2009 influenza A(H1N1)pdm09 vaccine during the 2010/11 season in Sweden Widgren, K and Magnusson, M and Hagstam, P and Widerström, M and Örtqvist, Å and Einemo, I M and Follin, P and Lindblom, A and Mäkitalo, S and Wik, O and Österlund, A and Grünewald, M and Uhnoo, I and Linde, A, Eurosurveillance, 18, 20447 (2013), https://doi.org/10.2807/ese.18.15.20447-en