Interim 2022/23 influenza vaccine effectiveness: six European studies, October 2022 to January 2023., Kissling, Esther, Maurel Marine, Emborg Hanne-Dorthe, Whitaker Heather, McMenamin Jim, Howard Jennifer, Trebbien Ramona, Conall Watson, Findlay Beth, Pozo Francisco, et al. , Euro Surveill, 2023 May, Volume 28, Issue 21, (2023)