The exact mechanism of action of the COVID vaccines is not yet fully understood, however there are a few theories that are currently being studied.
One theory is that the vaccines work by triggering an immune response in the body. The vaccine contains a weakened form of the virus which is not capable of causing an infection, but is enough to alert the body’s immune system. When the body is exposed to the weakened virus, it recognizes it as a foreign invader and begins to produce antibodies to fight off the virus. This process enables the body to build immunity to the virus, thus protecting the person from becoming infected if they are exposed to it in the future.
Another theory is that the vaccines may work by stimulating the production of T cells, which are a type of white blood cell that is important for mounting an immune response. The vaccine may stimulate the production of T cells, which can then recognize and kill the virus if the person is exposed to it.
Finally, the vaccines may work by activating a process known as antigenic drift. This process occurs when the virus mutates, or changes its structure, making it harder for the immune system to recognize it. The vaccine works by stimulating the body's immune system to recognize and respond to the mutated virus, thus making it easier for the body to mount an effective immune response if the person is exposed to the virus.
Overall, the exact mechanism of action of the COVID vaccines is still being studied, but the current theories suggest that the vaccines work by triggering an immune response, stimulating the production of T cells, and activating antigenic drift.