He is the principal investigator of several observational studies involving mostly men who have sex with men (MSM) and female sex workers (FSW) in Kilifi, and co-recipient of the SANTHE grant. His interest in diagnosing acute HIV infections was inspired by the many MSM who sought health care prior to seroconversion in coastal Kenya, and the opportunity this presents for reducing onward HIV-1 transmission. He currently leads ongoing studies on the utility of clinical algorithms to identify and diagnose young adults with acute HIV infection at various health facilities in Kenya, enabling early treatment, counselling interventions, and assisted partner notification.