Acute flaccid paralysis (AFP) surveillance: challenges and opportunities from 18 years’ experience, Spain, 1998 to 2015 Masa-Calles, Josefa and Torner, Nuria and López-Perea, Noemí and Torres de Mier, María de Viarce and Fernández-Martínez, Beatriz and Cabrerizo, María and Gallardo-García, Virtudes and Malo, Carmen and Margolles, Mario and Portell, Margarita and Abadía, Natividad and Blasco, Aniceto and García-Hernández, Sara and Marcos, Henar and Rabella, Núria and Marín, Celia and Fuentes, Amelia and Losada, Isabel and Gutiérrez, Juan García and Nieto, Alba and Ortúzar, Visitación García and Cenoz, Manuel García and Arteagoitia, José María and Martínez, Ángela Blanco and Rivas, Ana and Castrillejo, Daniel and Spanish AFP Surveillance Working Group, Eurosurveillance, 23, 1700423 (2018), https://doi.org/10.2807/1560-7917.ES.2018.23.47.1700423