The doctor also reiterated that measles is highly contagious, and "spreads rapidly through pockets of our community where there are people who are unvaccinated or have no immunity to measles."

Many of those pockets are Mennonite and Amish religious communities, which contain high concentrations of unvaccinated people, Ontario's top doctor Kearon Moore said in a letter to health units back in March.

According to Tran, outreach documents about vaccinations have been translated into Low German. SWPH is also working on outreach efforts geared toward summer camps and seasonal agricultural workers.