1. Broegelmann Research Laboratory, Haukeland University Hospital, Bergen, Norway
2. Department of Obstetrics and Gynaecology, Haukeland University Hospital, Bergen, Norway
3. Department of Microbiology, Trondheim University Hospital, Trondheim, Norway
4. Department of Oral Biology, University of Florida, Gainesville, Florida, USA
5. Department of Vaccinology, National Institute of Public Health, Oslo, Norway