Refrigeration is required for the oral typhoid vaccine to maintain its potency and effectiveness. It should be shipped and stored refrigerated between 35.6°F–46.6°F, which requires specialized packaging and overnight shipping. The live attenuated bacteria in the capsules need to be kept at a stable, cold temperature to ensure they remain viable and capable of stimulating an immune response. Failure to store the vaccine properly can reduce its efficacy and compromise the protection it provides. Always follow storage instructions and keep the vaccine refrigerated until use.