John Gachohi, PhD, is an epidemiologist with the School of Public Health, Jomo Kenyatta University of Agriculture and Technology in Kenya and Washington State University, Global Health Kenya. Within classical epidemiology, John has interests into how multiple medical conditions cluster and interact in vulnerable populations particularly women and girls. As the interactions can be biological, bio-behavioral, psychological, or social and driven by political, economic, and ecological factors, John is specifically interested in the methodological rigour relevant in better understanding these challenges termed syndemics. He is involved in designing and implementing syndemic studies for understanding the basis and pathways of harms faced by these vulnerable populations. Subsequently, he specializes in assessing how harms can be reduced in the short-, mid- and longer-term. To achieve this goal, John employs methodological pluralism that includes statistical modelling, mathematical simulation modelling, human-centered designs, socio-network analyses, agent based modelling and machine learning techniques to gain a deeper insight into the full nature of syndemics and harm reduction.