Resident, Medical Dept., County Hospital, Nykøbing F 01.08.1968 - 31.07.1969
Resident, Surgical/Gynaecological/Obstetrical Dept., County Hospital, Nykøbing F 08.08.1969 - 28.02.1970
Resident, Medical Dept. C, County Hospital, Gentofte 01.03.1970 - 31.08.1970
Resident, Statens Seruminstitut, Dept. of Clinical Microbiology, Blegdamshospitalet 01.09.1970 - 31.10.1972
Research Fellowship 01.11.1972 - 30.04.1975
Resident, Statens Seruminstitut, Dept. of Clinical Microbiology, Hvidovre Hospital 01.05.1975 - 31.12.1976
Resident, Statens Seruminstitut 01.01.1977 - 31.12.1978
Resident, Statens Seruminstitut, Dept. of Clinical Microbiology, Rigshospitalet 01.01.1979 - 31.03.1979 & 01.12.1979 - 29.02.1980
Resident, Rigshospitalet, Dept. of Infectious Diseases 01.04.1979 - 30.09.1979
Temporary Head of Dept. of Clinical Microbiology, Rigshospitalet 01.10.1979 - 30.11.1979
Senior Resident, Statens Seruminstitut, Dept. of Clinical Microbiology, Rigshospitalet 01.03.1980 - 22.06.1980
Temporary Head of the Statens Seruminstitut, Dept. of Clinical Microbiology, Rigshospitalet 23.06.1980 - 31.03.1981
Chairman of the Statens Seruminstitut, Dept. of Clinical Microbiology 01.04.1981 – 31-8-2012
Head of the Statens Seruminstitut, Dept. of Clinical Microbiology 01.09.2012
senior resident Statens Seruminstitut, Dept. of Clinical Microbiology
Associate Professor of Medical Microbiology, University of Copenhagen 01.09.1983 - 31.08.1988
Professor of Medical Microbiology, University of Copenhagen 01.09.1988 to present
Visiting professor, University of Hannover Medical School 1989
Professor honoris causa, Guangxi Medical University, Nanning, China 1998
Visiting professor, Chinese PLA Postsgraduate Medical School & Chinese PLA General Hospital, Beijing, China 2011
Professor honoris causa, West China School of Stomatology, Sichuan University, Chengdu, China 2011
Visiting professor 2018-2021, Peoples University Hospital, Youjiang Medical University for Nationalities, Baise, Guangxi, China 2018