Charlie first got sick at 9 months and was pretty much sick that entire winter and spring. He had a nanny but went to a lot of indoor playspaces. He had a respite in the summer and early fall, then was sick the entire winter/spring again through his second year.

By the time he was 3 he was definitely getting sick way less. And now at 4, he's only been sick once this winter season despite starting public school.

So his immune system definitely got better as he got older!