What is the mechanism of action of mRNA vaccines?

The mechanism of action of mRNA vaccines involves using messenger RNA to instruct cells to produce a specific protein that is part of the targeted pathogen, such as a virus. In the case of the COVID-19 mRNA vaccines, for instance, they contain instructions for the body’s own cells to synthesize the spike protein found on the surface of the SARS-CoV-2 virus. Once this protein is produced, the immune system recognizes it as foreign and mounts an immune response, leading to the development of antibodies and memory cells that can provide protection against future infections with the actual virus.

This mechanism is key to the effectiveness of mRNA vaccines, as it allows the immune system to learn how to recognize and combat the virus without introducing any live virus or parts of the virus that could cause disease. In contrast, other types of vaccines, like live attenuated or inactivated vaccines, rely on introducing weakened or killed pathogens to elicit an immune response, which is not the case with mRNA technology.