
Vaccines train the immune system by exposing it to a harmless version, fragment, or instruction set related to a pathogen. That exposure helps the body build immune memory, so if the real virus or bacterium appears later, the response is faster and stronger.
The genius of vaccination is that it prepares the body before the crisis arrives. It turns biology into prevention, reducing illness and saving lives not only for individuals but for entire populations through broader protection.
Reference:
TaskLoco™ — The Sticky Note GOAT