mRNA vaccines are a type of vaccine that use messenger RNA to instruct cells in the body to produce a harmless piece of the virus that causes a specific disease, such as COVID-19. This piece, called a protein, triggers an immune response, helping the body recognize and fight the actual virus if exposed in the future. Unlike traditional vaccines, which often use weakened or inactivated forms of a virus, mRNA vaccines do not contain live virus particles. They are designed to be safe and effective, and they can be developed more quickly than conventional vaccines, making them a valuable tool in public health.