Study protocol for a pre/post study on knowledge, attitudes and behaviors regarding STIs and in particular HPV among Italian adolescents, teachers, and parents in secondary schools oleh Laura Brunelli, Laura Brunelli, Francesca Valent, Manola Comar, Manola Comar, Barbara Suligoi, Maria Cristina Salfa, Daniele Gianfrilli, Franz Sesti, Vincenzo Restivo, Alessandra Casuccio, ESPRIT Study Collaboration Group, Silvia Gazzetta, Lorenza Driul, Andrea Isidori, Patrizia Ferro, Nicoló Piazza, Palmira Immordino, Giuseppina Capra, Teresa Fasciana