Universal vaccine access is an existing major challenge in low-income countries, mainly due to the lack of robust cold-chains, resulting in loss of potency for +25% of vaccines. Mass vaccination for COVID-19 globally will require a new fast-track approach to assess, re-engineer and build upon available cold-chain logistics assets and systems, to deliver the vaccines at scale and speed never before considered. We aim to evaluate the capacity and preparedness of the cold-chain framework of Bangladesh as a case study country for mass scale COVID-19 vaccination, and assist the policymakers in defining optimised, sustainable interventions and lasting legacy opportunities. Our objectives are: (1) evaluating the context and resilience of cold-chains and resources in Bangladesh, collecting primary data for a robust assessment of the cold chain capacity and gaps; (2) developing a bottom-up whole systems approach building upon existing logistics infrastructure, and distribution systems for mass scale COVID-19 vaccination including modal shifts; (3) developing a cost-benefit analysis framework for the bottom-up (vaccine) systems model; (4) assessing different intervention scenarios for mass-scale COVID-19 vaccination preparedness, and helping shape the country's immunisation strategies and priorities; (5) informing policymakers and other key stakeholders, including Monetary Financial Institutions about the cost-effective intervention alternatives for cold-chain development for mass-scale vaccination for COVID-19, which may be useful for future emergency or disasters; and (6) disseminating learnings to other countries, including methodology, to assess their requirements and to simulate best options for creating sustainable temperature-controlled supply-chains for health and medical supplies in epidemics and natural disasters.