1. Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden; Division of Clinical Virology, Department of Microbiology, Pathology, and Immunology, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden and Division of Virology, Department of Medical Microbiology, Dermatology, and Infection, Lund University, Sweden
2. Division of Clinical Virology, Department of Microbiology, Pathology, and Immunology, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden
3. National Institute of Biological Standards and Control, South Mimms, Potters Bar, Herts, UK
4. Division of Virology, Department of Medical Microbiology, Dermatology, and Infection, Lund University, Sweden