trotsky and Mineral Man have said.
I'm old enough (63) to have gotten all the old childhood disease. My two sons got chicken pox, and first son got Fifth Disease.
My mother was born in 1916 and I once asked her if she'd ever seen smallpox (she became a nurse in the 1930s) and she said no, but there was a family on her street when she was young that had several members come down with smallpox because they hadn't been vaccinated.
My sister's oldest (now 28) had several bouts of scarlet fever as a child, but for reasons I don't fully understand, scarlet fever became vastly less virulent during the 20th century, and now is no big deal as long as it's treated -- with antiobiotics, I think, but I'm not sure.
What we're all used to anymore is that people die from accidents or various cancers or heart disease, not the viral and bacterial illnesses that used to carry us off. I have seen charts showing the changes in the leading causes of death, and even if you don't know much else, you can see the impact of vaccines, better nutrition, and (this is the real biggie) vastly improved sanitation.
With regards to that last, every time I hear or read people freaking out about the possibility of another flu pandemic as in 1918, I point out that there are substantial differences in many things since then, not the least of which is indoor plumbing and a vast increase in hand washing.
I once read that in the 19th century many more people died from stomach cancer than do today because of changes in food preservation. Apparently older methods tended to induce stomach cancer.