Finding a right balance between the workload demand for vaccination and healthcare workforce size is key to having vaccination work systems that can support the fulfillment of immunization goals. This load-workforce balance can only be achieved when there is a framework for estimating the workload in various vaccination scenario. The study considers the development of a framework to categorise vaccines based on work requirements for estimation of workload. A framework was developed based on vaccines available for routine immunization schedules in Nigeria. The framework groups the vaccines based on similarity of vaccine administration routes, vaccine preparation for administration, demography of vaccinees and or caregivers in order to define their work requirements. The proposed framework will aid decision-makers in estimating workload of vaccination work system