Preston is a public health specialist with over 19 years’ experience working in health and development across multiple countries in sub-Saharan Africa. He has worked both in the public and private health sectors, initially providing services as a clinician and subsequently transitioning to managerial and strategic roles for various service delivery and disease control institutions and programs. He has hands-on expertise in areas such as designing, implementing, monitoring and evaluation of disease control interventions; quality improvement (QI) and quality assurance (QA) systems and processes in health; leading multi-disciplinary teams to deliver on various tasks; providing technical and strategic support to various entities; and undertaking scientific research in health. Preston holds a bachelor’s degree in medicine (MBChB) from the University of Nairobi, a master’s degree in public health (MPH) from Moi University, a diploma in Vaccinology from the Institut Pasteur, and has attended numerous short course trainings in health from different institutions across the globe.