Conclusion
The early detection and prevention of COVID-19 should focus on hospital outpatients, emergency room patients, and individuals entering or leaving an area with known or suspected infections. The introduction and implementation of the concept of “vital sign zero” should be used before taking baseline measurements of breathing, heartbeat, blood pressure, and other vital signs. Based on the information collected, medical workers take appropriate personal protective measures that reduce the probability of becoming infected. At the same time, the “3I System” should be used to detect patients with COVID-19 as early as possible, so that isolation and reporting can be performed according to the predetermined plan to prevent the spread and reduce the prevalence of this disease. For potentially infectious patients, especially highly infectious patients, the “3I System” provides a simple and effective template for management. Because of COVID-19 and other emerging infectious diseases, the establishment of such a system could provide significant benefits to public health.