Statens Serums Institut - Infectious Disease Epidemiology & Prevention, University of Copenhagen, Statens Serums Institut - Infectious Disease Epidemiology & Prevention, Umeå University, Statens Serums Institut, affiliation not provided to SSRN, Aarhus University, Aarhus University, Aarhus University, Aarhus University, Roskilde University and Statens Serums Institut