Over the past year, only a few cases with coronavirus disease 2019 (COVID-19) were identified in Taiwan under active and detection of traveling and contact history measures on confirmed cases, besides imposing a quarantine on inbound travelers and people with contact history. Unfortunately, in May 2021, a large-scale COVID-19 outbreak occurred in Wanhua District, Taipei City. I participated in caring for adult patients with COVID-19 together with other pediatricians. The treatment included basic symptom treatment, hypoxia avoidance, and adequate control of the patients' co-occurring chronic diseases. During the process, close cooperation with medical professionals of other departments was crucial. Moreover, we provided the patients and their families with immediate disease condition analysis and the latest treatment and therapeutic knowledge to jointly decide the treatment method and maximize the patient benefits.