Parents are being reminded to check their vaccinations are up-to-date, as the school gates re-open.
Thirteen cases of measles have been confirmed in the past month, and it's feared the number will climb as young people return to school tomorrow.
But Dr Caroline McElnay from the Ministry of Health says strangely, the confirmed cases aren't kids.
"We're actually seeing cases of people in their 30s and early 40s. Those people, back in the day when they were children, they only had one dose because that's all that was on the schedule."
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Dr McElnay says our vaccination rates for kids are good, taking some off the pressure off, but mum and dad might want to check their own immunity.
"Now's the time to make sure you're up to date with your immunisations - which means having two doses of the MMR vaccine if you [were born after] 1969."
The more people who are immunised, the less likely those who can't be immunised or are too young to have their jabs will contract the disease, through what's known as 'herd immunity'.