Just 70 per cent of seven year olds in Ontario were fully vaccinated against measles last year, according to Public Health Ontario.

That represents a steep drop in vaccination coverage compared to before the COVID-19 pandemic, according to the data. There have been similar declines for other routine childhood vaccines as well.

A decade ago, during the 2013-14 school year, 94 per cent of seven year olds in Ontario were fully immunized against measles. That number has steadily declined since then. Herd immunity for measles, which is among the most contagious infections in the world, is between 90 and 95 per cent.