1. Department of Microbiology, Public Health Agency of Sweden, Solna, Sweden;
2. Center for Medical Technology Assessment, Department of Medicine and Health, Linköping University, Linköping, Sweden;
3. Department of Woman and Child Health, Astrid Lindgren Children´s Hospital, Karolinska University Hospital, Stockholm, Sweden;
4. Department of Vaccine-Preventable Illnesses, National Public Health Institute, Oslo, Norway