In the 19th century, smallpox was widely considered a disease of filth, which meant that it was largely understood to be a disease of the poor. According to filth theory, any number of contagious diseases were caused by bad air that had been made foul by excrement or rot.

Lead, kindly Light, amid the encircling gloom,/ Lead thou me on;/ The night is dark, and I am far from home,/ Lead thou me on.

And with the morn those angel faces smile/ Which I have loved long since, and lost awhile.

To holy people the very name of Jesus is a name to feed upon, a name to transport. His name can raise the dead and transfigure and beautify the living.

As for the comparatively small class of violent crimes against persons, unconnected with any idea of gain, they were almost wholly confined, even in your day, to the ignorant and bestial; and in these days, when education and good manners are not the monopoly of a few, but universal, such atrocities are scarcely ever heard of.

I think that protecting children at the age where they're most vulnerable against diseases that are highly contagious is prudent.