During the COVID-19 pandemic, I had the opportunity to contribute to a crucial project in collaboration with Universitas Gadjah Mada and Kimia Farma: the COVID-19 Self-Report Application (Aplikasi Pelaporan Mandiri). This application was designed to track vaccine recipients and monitor potential adverse events following immunization (AEFI) across various timeframes, from minutes to weeks, after receiving vaccines such as AstraZeneca and Sinovac. This data provided valuable insights for Kimia Farma, enabling them to optimize treatment protocols for recipients. Furthermore, the application also tracked participants' exposure to COVID-19, contributing to improved public health efficiency and response strategies.