The first two reported cases of measles in Northland are within the expectations of the DHB there, but there are fears a low immunity rate could mean it spreads to vulnerable people in the region.
An 11-year-old visitor to Northland from Auckland has been diagnosed and a 14-month-old from Australia is suspected to have the disease. Both went to the Bay of Islands Hospital over the weekend.
Medical officer Virginia McLaughlin from the DHB said they are very concerned and will keep a close eye on the nearly 50 people known to have been potentially exposed.
"I think people might have forgotten just how serious measles is. We need to remember that this is a highly infectious and really severe infection. People can die from measles. People can get very severe complications," she said.
She said the disease can be easily prevented by routine vaccination and urged people to have one.
It has been estimated that to prevent recurrent outbreaks of measles, 95 percent of the population must be immune, but Northland has a low rate of 86 percent, according to Dr McLaughlin.
"That means if measles comes in, it can actually spread and it can spread to our most vulnerable babies and children who are too young to be immunised."
She added that they might look to make immunisation compulsory.
"If you are found to be a contact of a case of measles and not immune, you will need to stay away from work, school or public places for up to 14 days, to help prevent putting other people at risk," Dr McLaughlin said.
She said the last outbreak in Northland was in 2016, when six people were diagnosed.