A major focus of his research has been to provide the scientific evidence underpinning efforts to eliminate viral hepatitis as a public health threat through investigation of disease burden, modelling, and clinical studies (PROLIFICA, STOPHCV consortia, STOPHCV-1 trial). He currently leads the SEARCH collaboration conducting strategic treatment trials for hepatitis C in Vietnam (in collaboration with OUCRU and MRC Clinical Trials Unit) and the Lancet journals Commission on accelerating the elimination of viral hepatitis.
In response to COVID19, he co-ordinated the virtual COVID theme of the NIHR Biomedical Research Centre and was a member of the WHO COVID-19 treatment guidelines group. He led clinical development of the COVIDnudge diagnostic and is a PI for the REACT studies which have recruited over 3 million people to self-testing studies for COVID19.