Vaccine development is the process of creating a vaccine to help prevent diseases. It typically involves several stages, including research, preclinical testing, and clinical trials. Scientists study the disease-causing agent, such as a virus or bacteria, to understand how it affects the body and how to stimulate an immune response. Once a potential vaccine is identified, it undergoes rigorous testing to ensure its safety and effectiveness. This includes trials with volunteers to monitor any side effects and measure how well the vaccine works. If successful, the vaccine can be approved for public use, contributing to public health efforts against diseases like COVID-19 or influenza.