Seasonal influenza vaccination among health-care workers: the impact of different tailored programs in four University hospitals in Rome oleh Alessia Tognetto, Ermanno Zorzoli, Elisabetta Franco, Giuseppe Gervasi, Lorenzo Paglione, Filippo Di Ninno, Pasquale De Soccio, Andrea Barbara, Giovanni Battista Orsi, Corrado De Vito, Giuseppe La Torre, Roberto Bucci, Sandro Mancinelli, Massimo Maurici, Patrizia Laurenti