Except where otherwise noted, this item's license is described as 2020 Published by Elsevier Espa ̃na, S.L.U. on behalf ofAsociaci ́on Espa ̃nola de Pediatr ́ıa. This is an open access articleunder the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).(http://creativecommons.org/licenses/by-nc-nd/4.0/)