Background and Objectives: An outbreak of coronavirus disease 2019 occurred in mid-May of 2021 in Taiwan. After 2 months of hard work, transmissions were successfully prevented and the number of newly confirmed COVID-19 cases fell remarkably. We evaluated the impact of this outbreak on the massive transfusion protocol (MTP) in the emergency department (ED) of a trauma centre. Materials and Methods:We retrospectively compared the activation and efficacy of MTP before, during and after the outbreak by analysing the clinical data relevant to MTP activations.Results: There was no remarkable change in the average number of MTP triggers per month during the outbreak. The interval from an MTP trigger to the first unit of blood transfused at bedside was significantly increased during the outbreak compared to that before the outbreak (22.4 min vs. 13.9 min, p < 0.001); while the 24-h survival rate decreased (57.1% vs. 71.1%, p = 0.938).There were no remarkable changes in blood unit return or wastage during the outbreak. Conclusion:The COVID-19 outbreak limitedly affected MTP activation and waste of blood products, but significantly increased the interval from an MTP trigger to the first unit of blood transfused at bedside.