COVID-19 vaccine trials refer to the rigorous testing processes conducted to evaluate the safety, efficacy, and immunogenicity of potential vaccines against the SARS-CoV-2 virus, which causes the COVID-19 disease. These trials typically involve multiple phases, including preclinical studies in animals, followed by human clinical trials divided into Phase 1, Phase 2, and Phase 3, each with increasing numbers of participants. These trials assess the vaccine's ability to produce an immune response, its safety profile, and its effectiveness in preventing COVID-19 infection or reducing its severity. Regulatory authorities closely monitor these trials to ensure ethical standards, safety, and scientific validity. Successful trials lead to regulatory approval and subsequent vaccination campaigns to combat the spread of COVID-19.