The development of vaccines involves several stages. Initially, researchers identify the pathogen and understand its biology. They then select appropriate antigens that can trigger an immune response. Preclinical studies using cell cultures and animal models test the vaccine's safety and efficacy. Following successful preclinical trials, the vaccine undergoes multiple phases of clinical trials in humans. Phase I focuses on safety, Phase II evaluates immunogenicity and optimal dosing, and Phase III assesses the vaccine's effectiveness in a larger population.
