ABSTRACT
Due to COVID-19, many countries including Japan have implemented a suspension of economic activities for infection control. It has contributed to reduce the transmission of COVID-19 but caused severe economic losses. Today, several promising vaccines have been developed and are already being distributed in some countries. Therefore, we evaluated various vaccine and intensive countermeasure strategies with constraint of economic loss using SEIR model to obtain knowledge of how to balance economy with infection control in Japan. Our main result is that the vaccination strategy that prioritizes younger generation outperformed the other strategies in terms of deaths. On the other hand, when we focused on strategies that prioritize older generation, as Japan has decided to do, the optimal vaccination strategy was determined by the basic reproduction number and acceptable economic loss. The strategy vaccinating the young next to the old age group was the best when acceptable economic loss was high, or the basic reproduction number was low. Alternatively, the strategy vaccinating the middle next to the old age group was superior to the others with a moderate acceptable economic loss and the high basic reproduction number setting.
