A near-miss has prompted a warning from health authorities after 15 New Zealanders were exposed to measles on a recent flight from Australia.
It comes as cases surge globally, with outbreaks linked to plummeting vaccination rates.
New Zealand's 2019 measles epidemic was the worst in two decades and spread to Samoa.
More than 80 lives were lost, and most of them were children.
Now there are fears it could happen again.
"I've been deeply concerned about measles for a long period of time," Health Minister Dr Shane Reti said.
In a statement issued on Wednesday, Te Whatu Ora warned unvaccinated Kiwis not to travel overseas as measles cases surge across the globe.
The health agency said 15 people travelling to New Zealand two weeks ago had been exposed to a measles case in Australia.
Fourteen of them were immune and one has been quarantined.
"This is a strong reminder that if people want to avoid the risk of becoming seriously ill while travelling, or while enjoying their overseas holiday, they need to make sure they are fully immunised with two doses of a measles vaccine before they go," clinical lead Dr William Rainger said in a statement.
"Being immunised also protects those around you from becoming seriously ill and from spreading the disease to others," he added.
And with plummeting vaccination rates, it could mean next time Kiwis might not be so lucky.
"I think every time we get a positive measles outbreak, most of the clinicians like myself hold our breath," Reti said.
"We think 'Oh goodness, I hope that's isolated'", he said.
"I hope the index case is isolated and doesn't progress, because with the immunisation rates we have at the moment, we would be at risk."
There has been a sharp drop in rates since coverage peaked in 2017, down by almost 10 percent.
For Māori, those rates have fallen off a cliff - they are more than 24 percent below the 2017 rates, and it's a similar story for Pasifika children.
New Zealand's critically low vaccination rates are part of a global trend.
"The COVID-19 pandemic significantly affected regular childhood immunisation schedules for many," Immunologist Dianne Sika-Paotonu told Newshub.
The UK Health Security Agency has declared a national incident with more than 200 confirmed measles cases.
In Europe, the World Health Organisation has issued an alert after a 45-fold increase.
There are similar concerns in the United States, Asia, the Middle East and now Australia, where two babies are seriously ill.
However, the infectious disease is preventable.
"It's fantastic that we have a vaccine readily available here in Aotearoa New Zealand that is highly effective, but also precents the spread of measles to others," Sika-Paotonu said.
In a bid to lift vaccination rates, Reti is reinstating a target.
"Immunisation will be one of the targets, one of the most important targets, that we apply a lot of attention and a lot of focus to during this coming term of Government," he stressed.
It's one more thing for Kiwis to consider before jetting off overseas.
