After qualification as a physician, Grange joined the Research Department at the Middlesex Hospital, where he studied the genus
Mycobacterium and the diseases it causes in humans and other animals. This followed a stay in
Zaire to study the
Buruli ulcer. His doctoral
thesis was on the classification of certain rapidly growing
mycobacteria and led to research on the development of
bacteriophage typing of mycobacteria for
epidemiology. Next he was appointed Reader in
Microbiology at the
National Heart and Lung Institute, where his interests turned to the
immunology and
epidemiology of
tuberculosis. From there he became assistant lecturer (1969-1970) at the
Bland Sutton Institute of Pathology of
Middlesex Hospital Medical School,
University of London and then lecturer in the same school's
Department of Microbiology from 1971 to 1976. From 1976 to 2000, Grange was Reader in Clinical Microbiology at the
Imperial College School of Medicine and honorary consultant Microbiologist to the Royal Brompton NHS Trust. Between 1978 and 1995, he undertook a series of visits to
Indonesia to pursue research into the
immunology and
epidemiology of
tuberculosis. From 1985 to 1995, he was an honorary research fellow at ''King's College Hospital Medical School
. After retirement from ICL he became a visiting professor at the University College London Centre for Infectious Disease and International Health''. In his later years, Grange's interests turned to the causes of the world
tuberculosis pandemic - poverty, inequity and injustice. He retired early from
Imperial College London and to work for the British charity
TB Alert, the
Consultation on Health of the
World Council of Churches and the
International Society for Human Values. ==Career related activities==