There’s a reason it’s called the common cold – because so many people catch it. Famously, there is no cure (yet), mainly because what you know as the cold is caused by an endless array of viruses. Just because you get a cold once doesn’t confer immunity against having another (and another).
You or your child can catch a cold from droplets in the air after someone coughs, sneezes, or talks, and by touching contaminated objects like toys, phones, towels, and utensils. If you touch a contaminated object and then touch your eyes, nose, or mouth, you are likely to catch a cold.