Experience with measles in Canada and the United States.

The United States is attempting to eliminate indigenous measles by October 1982. Progress in this effort appears to be related largely to the fact that all children must now be vaccinated before starting school and that unvaccinated children are not allowed to attend school during epidemics. Canada has not yet made a similar concerted effort to eliminate measles. The epidemiologic features of the disease in Canada and the United states have generally been similar, but some differences have emerged in recent years: Canadian rates are currently about 10 times higher, and the highest incidence in Canada is still in children 5 to 9 years of age, whereas in the United States the highest incidence is now in children aged 10 to 14 years, the result of intensive vaccination programs for preschool and early school-aged children.