Measles is currently spreading in the community, putting New Zealand at risk of a larger outbreak, Health New Zealand Te Whatu Ora says.

The total number of cases to date is 13, and Auckland schools including Auckland Grammar School are telling students to stay home after exposure to measles. The risk of further cases, contacts and exposure is “very high”, according to the public health agency.

Experts say a higher level of immunity is needed to prevent transmission of the virus. But what is measles, what are the symptoms and how do you know if you’re immune? Here’s what you need to know.

What are the symptoms of measles?

According to Health NZ, measles is an acute respiratory illness caused by the measles virus, which is highly contagious.

Early symptoms typically include a fever, cough and conjunctivitis or red eyes, around 10 days to two weeks after being exposed to the virus.

A measles rash usually develops a few days later, starting on the face or behind the ears and spreading downwards to the rest of the body. It’s important to note that not everyone with measles will get a rash.

Dr Prabani Wood, a Hamilton-based GP and medical director of the Royal New Zealand College of GPs, says most people will recover quickly, but the virus can lead to serious health impacts in some cases.

“You can get pneumonia as a result of having a recent measles infection,” she tells the Herald.

“There’s a very rare but very serious instance where you get essentially swelling and inflammation around the brain after having measles. It can also cause deafness.

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“At least 10% of people that get measles end up with serious illness and serious follow-on side effects from it, which [lead to] sometimes long-term hospitalisation and even death.”

What’s the current vaccination rate for measles in New Zealand?

Not high enough, according to the experts.

Speaking to The Front Page host Chelsea Daniels earlier this week, University of Canterbury senior lecturer in epidemiology Anna Howe said we’re in an “extremely precarious position”.

A population immunity of around 95% is needed to prevent transmission once the virus has been introduced.

“At the moment, our childhood schedule provides MMR [measles, mumps and rubella vaccine] at 12 and 15 months. So, we use our 24-month coverage milestone as an indicator ... coverage is sitting at 82%,” Howe said.

“That coverage is not uniform across the community, even at 82%.”

Regions like Northland and Lakes have low coverage, 62-73%, she said, while the Hutt Valley, Capital and Coast, and Canterbury have 90%.

When should you get vaccinated for measles in New Zealand?

According to Health NZ, there are two ways to become immune to measles: by having had it before or by getting two doses of a measles vaccine after the age of 12 months.

This is known as the combination MMR – measles, mumps and rubella – vaccine, which is given to children at the age of 12 and 15 months according to the current schedule. It was first introduced to New Zealand in 1990.

Health Minister Simeon Brown is currently considering advice on an MMR zero vaccination for babies aged 4 months to under 12 months.

“Ultimately, the advice or the early advice I’ve received is that it is an option which will be considered, but there’s also a potential downside in that if children are immunised earlier than one year, then potentially the longer-term immunity isn’t as good or the effectiveness of the vaccine isn’t as good over the longer term,” he told Newstalk ZB.

How do I know if I’ve been vaccinated for measles?

According to Health NZ, if you were born before 1969, you’re likely to be immune to measles. As there was no measles vaccine at this time, many people would have had measles as children.

For those people who have had vaccinations, you may have immunisation records that can tell you if you’ve had both doses of the measles vaccine.

These may have been recorded in your Wellchild or Plunket book, electronically on My Health Record, or your doctor may be able to share them with you through an online portal such as My Indici or Manage My Health.

The information in these records may differ, depending on when and where you received your vaccinations. You may have been given the MMR vaccine, or, if you were vaccinated before 1990, you may have received the measles vaccine (before 1981, this was given to babies at 10 months, rather than the current 12 months).

You can also put the year you were born into this tool on Health NZ’s website for guidance.

If you can’t find any record of your measles vaccine, you can speak to your GP about getting a blood test or swab for measles.

What to do next?

The current measles outbreak may get worse before it gets better.

“It’s just a case of waiting a few more weeks, probably to see how bad it’s going to get,” Howe said.

Wood’s advice to anyone who thinks they might have measles symptoms is to stay at home and if they get worse, call Healthline or your GP.

“They can link them to the public health units around the country who are trying to do contact tracing, so they’ll try to confirm whether this is a measles case or not,” she says.

“Stay home, try and rest up, but obviously be aware if you’re starting to get more unwell, to seek out medical care.”

If you are considered not immune to measles, you can get vaccinated, with two MMR vaccines at least one month apart. The vaccine is free to everyone in New Zealand under the age of 18, and if you are 18 or older, it is free if you are eligible for funded healthcare in Aotearoa.

If you’re pregnant, taking immunosuppressant medication or were born before 1969, speak to your doctor before getting the measles vaccine.