Vaccine adjuvants are substances added to vaccines to enhance the body's immune response to the intended antigen. The primary goal is to improve the vaccine's efficacy by promoting a stronger, longer-lasting, and more robust immune reaction. Common adjuvants include aluminum salts (alum), which have been used for decades and are found in various vaccines. Other adjuvants include oil-in-water emulsions, liposomes, and virosomes. These adjuvants often stimulate a more significant production of antibodies and activate immune cells, contributing to a heightened defense against pathogens. Adjuvants play a crucial role in enhancing vaccine effectiveness, especially in situations where a strong immune response is needed, such as in certain populations or against rapidly evolving pathogens. They enable the use of lower vaccine doses while still achieving optimal protection. Research in vaccine adjuvants focuses on understanding their mechanisms of action, optimizing formulations, and ensuring safety. Balancing enhanced immunogenicity with minimal side effects is crucial in developing effective and well-tolerated vaccines for a variety of infectious diseases.