Clinician by background turned clinical epidemiologist with a focus on HIV and sexually transmitted infections, but also interest in (re)emerging viral infections. I have worked a total of 13 years overseas in Africa and Latin America/Caribbean.

I serve as member of WHO and UNAIDS expert panels on STI since 1993, and Zika since 2016.
I am a scientific expert with a number of French (ANRS, INSERM, Institut Pasteur, World AIDS Foundation), other international (US NIH, Canadian CIHR) research agencies, and in the UK (MRC).

I have served on the Scientific Board of CAREC (Caribbean Epidemiology Centre, Trinidad); and Wits Reproductive Health & HIV Research Institute, University of Witwatersrand, Johannesburg, South Africa.

I have been Head of the HIV Epidemiology and Intervention Programme and Theme Leader of HIV and Emerging Infections at the MRC/UVRI/LSHTM Uganda Research Unit based in Entebbe, Uganda from March 2019 to march 2020.

I have been Head of the LSHTM Department of Clinical Research during 2012-2016, and 2020-2021 (at start of COVID-19 pandemic; and helped coordinate the original clinical response of LSHTM to the pandemic.)

I have been a founding member, once Director, and current member of the WHO Collaborating Centre for Sexually Transmitted Infections at LSHTM. I Ama member of several research Centres at LSHTM (MARCH, Vaccine, Humanitarian Conflicts and Crises)

I hold a number of Honorary international positions: 1) Clinical Associate Professor at the School of Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (2009, renewed 2015); 2) Professor at the School of Public Health, University of Ghana, Accra, Ghana (2010-2015); 3) Visiting Professorship (2015-2018) at the Faculty of Medicine, University of Sao Paulo (FMUSP), Brazil, funded by CAPES/BRAZIL under the prestigious 'Ciencias sim Fronteiras' programme.