Relevance: The study of this locally manufactured new HL-OCV, among children and adults will be able to give us information regarding the safety and immunogenicity of two different formulations of vaccine, based on LPS content. The study will not only identify safe formulation among the two formulation A or B, but will also be able to show superiority of higher LPS formulation in most naive population in children who are 1-5 years of age. Results of the study will be able to identify and select most suitable formulation in Phase II study for licensure in Bangladesh. This study will further pave the way forward for field studies which could establish field efficacy of vaccine compared to existing vaccines in Bangladesh.