Prof Marsh established with colleagues a biomedical research programme in Kenya which over 25 years grew from a small project to an internationally recognised centre with 800 staff working in many African countries. His personal research group has made major contributions to our understanding of how humans become immune to malaria. He has a particular interest in building research leadership in African science and since 2014 has worked with colleagues in The African Academy of Sciences to establish a new pan African platform,  the Alliance for Accelerating  Excellence in Science in Africa (AESA). Prof Marsh contributes to a number of international advisory committees and is chair of the WHO Malaria Policy  Advisory Committee (MPAC).