Marco Di Marco1, Elvira D'Andrea2,3, Paolo Villari2. 1. Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy. marcodimarco@live.it. 2. Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy. 3. Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA.