Follow up of the Humoral Response in Healthcare Workers after the Administration of Two Dose of the Anti SARS-CoV-2 Vaccines-Effectiveness in Delta Variant Breakthrough Infections - Fernandez Rivas, Gema (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Barallat, Jaume (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Quirant, Bibiana (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; González, Victoria (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Doladé Botías, María (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Martínez Cáceres, Eva María (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Piña, Monica (Institut Català de la Salut) ; Matllo, Joan (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Blanco Guillermo, Ignacio (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Cardona, Pere-Joan (Institut Germans Trias i Pujol. Hospital Universitari Germans Trias i Pujol) ; Universitat Autònoma de Barcelona