Canadian public schools also require pupils to be vaccinated, and tested for contact with tuberculosis, too. The death toll from polio in particular is still fresh enough in memory to keep that regulation in place, reinforced by the damage done by occasional outbreaks of red measles. People who object to that mandate have to find private schools where the administration shares their opinions -- an expensive proposition -- or home-school their children.

Likewise, if you want to work in a Canadian restaurant, TB testing is mandatory. If you don't like it, tough.

The threat of smallpox is not limited to close contact with the sick in the acute stage of infection; the virus survives in dried exudate on their clothes and bedding. (In quarantine hospitals, all such contaminated materials were burned.) Surely you've heard of the accusations of "germ warfare" levelled against the early British military government in Canada, based on the distribution of contaminated blankets to the neighbouring First Nations. That was in the 1760s, and I don't think that virus has changed its habits.