1 Unit of Occupational Prevention and Protection, ASL Lecce, Lecce, Italy.
2 Azienda Ospedaliero-Universitaria Policlinico Umberto I, Rome, Italy; Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy. Electronic address: giancarlo.ceccarelli@uniroma1.it.
3 Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
4 Department of Medical Statistics and Epidemiology Unit, Campus Bio-Medico University, Rome, Italy.
5 Azienda Ospedaliero-Universitaria Policlinico Umberto I, Rome, Italy; Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.