The focus of this work is the African HIV epidemic. To this end, he leads research groups in Durban and Kimberley, having established long-standing collaborations in South Africa, cofounding the UKZN HIV Pathogenesis Programme in 1998.

He received an Elizabeth Glaser Paediatric AIDS Foundation Scientist Award in 1999, a Wellcome Trust Senior Clinical Fellowship from 2002-2015 and a Wellcome Trust Investigator Award in 2015.