Charles has been working in the HIV/AIDS field since the mid 1980s as a clinical academic, describing the clinical spectrum of AIDS in Africa, then conducting formative trials of disease prophylaxis and antiretroviral therapy. Aiming to get his research into policy and practice, he moved to WHO Geneva in 2001 to lead treatment and prevention scale-up, including 3by5. His team generated all treatment and prevention guidelines for resource-limited settings and published the landmark Lancet modelling study that sparked Treatment as Prevention.

 

In 2009 he moved to India as UNAIDS country coordinator to support the national response to HIV. He was appointed Head of the School of Public Health at The University of Queensland in 2013 and in 2014 became the first Queensland Professorial chair of HIV and STls. As a clinical researcher, he has published over 250 peer-reviewed papers, with 17,500+ citations. His Google H index is 67.