Effectiveness of different measures in reducing the daily number of moderate to severe cases of COVID-19

Objectives: Interventions for controlling COVID-19 can be classified into case-based (e.g., contact tracing and quarantining) and population-based (e.g., using masks and receiving vaccines) measures. The objective of pandemic control has now shifted from reducing the daily number of cases to reducing that of hospitalizations through vaccination. COVID-19 has started exhibiting flu-like characteristics. Therefore, in this study, we compared different measures in terms of their effectiveness in reducing the daily number of moderate to severe cases of COVID-19. Methods: The branching model developed by Hellewell (2020) was used for simulation. The epidemiological data of the Omicron variant and various hypothetical scenarios were analyzed. The outcome variable of our study was the daily number of hospitalizations under different measures and their combinations. Results: Population-based measures were more effective than case-based measures; however, their combination led to the best outcomes. If vaccination reduced the number of COVID-19-related hospitalizations, the focus was on increasing vaccine coverage to increase medical capacity rather than enhancing vaccine efficacy. Conclusions: While loosening case-based measures, the government must consider whether population-based measures can support this change. Furthermore, to reduce the daily number of moderate to severe cases of COVID-19, vaccine coverage, rather than vaccine efficacy, must be improved.