1. Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties “G. D’Alessandro”, University of Palermo, Via del Vespro 133, 90127 Palermo, Italy
2. Clinical Epidemiology Unit, Regional Reference Laboratory of Western Sicily for the Emergence of COVID-19, University Hospital “P. Giaccone”, Via del Vespro 133, 90127 Palermo, Italy
3. Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”, Via Marinuzzi, 90129 Palermo, Italy
4. Istituto Superiore di Sanità (ISS), Viale Regina Elena 299, 00161 Rome, Italy
5. Regional Health Authority of Sicily, Via Vaccaro 5, 90145 Palermo, Italy