1. Department of Infection Control, Diakonessenhuis, Utrecht, The Netherlands
2. Department of Pediatrics, Diakonessenhuis, Utrecht, The Netherlands
3. National Institute for Public Health and Environment (RIVM), Diagnostic Laboratory for Infectious Diseases and Perinatal Screening, Section Virology, Bilthoven, The Netherlands
4. Department of Medical Microbiology, Diakonessenhuis, Utrecht, The Netherlands