Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections Sundell, Nicklas and Dotevall, Leif and Sansone, Martina and Andersson, Maria and Lindh, Magnus and Wahlberg, Thomas and Tyrberg, Tobias and Westin, Johan and Liljeqvist, Jan-Åke and Bergström, Tomas and Studahl, Marie and Andersson, Lars-Magnus, Eurosurveillance, 24, 1900114 (2019), https://doi.org/10.2807/1560-7917.ES.2019.24.17.1900114