2504-3145 2504-3145 S2504-31452021000100001 10.1159/000516290 Portugal Portugal Portugal 30 04 2021 30 04 2021 39 1 1 2 1 1997 7 4 4 187-97 2 2018 3 3 2004 27 5 5 417-21 4 European Centre for Disease Prevention and Control 2021 5 2021 51 4 4 6 2009 30 1 1 175-201 7 2020 57 6 6 365-88