1. Infectious Diseases Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy
2. Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
3. Health Protection Agency, Metropolitan Area of Milan, Italy
4. Public Health and Prevention Office, Regional Health Authority, Emilia Romagna, Italy
5. Operative Unit of Clinical Microbiology, Laboratory of Virology, St. Orsola-Malpighi University Hospital, Bologna, Italy
6. Department of Specialised, Experimental, and Diagnostic Medicine, Operative Unit of Clinical Microbiology, Laboratory of Virology, St. Orsola-Malpighi University Hospital, University of Bologna, Italy
7. National Reference Laboratory for Measles and Rubella, Istituto Superiore di Sanità, Rome, Italy