Vaccine

Real World Example

Imagine you have a home security system that needs to be trained to recognize intruders. Just like how your security system uses practice scenarios to learn what an intruder looks like, a vaccine introduces your body to weakened or dead versions of a pathogen so it can learn to recognize and defend against the actual threat. In this analogy, the weakened or dead pathogens in a vaccine are like the intruder scenarios for your security system, both serving as safe practice runs to prepare for a real encounter.