Vaccine
Vaccine explained in an easy to understand way:
Imagine you're preparing for a big exam by taking practice tests that mimic the real thing. Just like these practice tests help you get familiar with the exam format and questions, a vaccine introduces your immune system to a weakened or dead version of a pathogen, so it knows how to respond when faced with the actual disease. In this analogy, the practice tests are like the weakened or dead pathogens in the vaccine, training your immune system (like your brain for the exam) to recognize and effectively deal with the real threat, providing you with immunity against the disease.
Practice Version
Vaccine: A substance made of weakened or dead pathogens, it gives the body immunity against disease. Vaccine. A vaccine helps the body recognize and fight specific germs more effectively.