Chemically modified spike mRNA was synthesised with lab designed 5’ and 3’ UTRs and validated functionally. The lyophilised mRNA-lipid nanoparticles were found to be stable at 4° C for up to a week that addresses a critical challenge in the transportation of mRNA vaccines. Promisingly vaccinated animals produced strong immune responses against spike protein and neutralised SARS-CoV-2 pseudovirus.