The low immunisation rate of Northland teenagers could help a measles outbreak spread across the region, health officials fear.
Northland District Health Board has confirmed a sixth case of measles in the region and Northland medical officer of health Clair Mills said the immunisation coverage in Northland teenagers was too low to stop the spread of measles.
The first four cases were related to a person who is believed to have contracted measles while at a regional kapa haka contest in Hamilton last month.
Dr Mills is advising Northlanders to ensure their families are protected from measles, to prevent further spread.
"Historically, vaccination coverage in Northland has been low. This means that only about 60 per cent of our teenagers are fully vaccinated against measles with two Measles.