Doctors at Hawke's Bay Hospital initially thought an infant with measles had the common cold as the illness can be difficult to diagnose in its early stages.
The family made two visits to the hospital's Emergency Department before the infant was diagnosed on Tuesday, July 16.
Three days before, the family had taken the infant to ED, and were sent home with what doctors believed was a cold as the infant was not displaying measles symptoms.
The infant had contracted the highly contagious airborne disease while visiting Auckland.
The infant was not old enough to be immunised against the virus. The Measles, Mumps and Rubella (MMR) vaccine is routinely given at 15 months and 4 years of age.
Medical Officer of Health Dr Nicholas Jones said when the infant first presented to ED there was no clinical suspicion of measles.
"There was no known measles contact at this point. When the infant presented to ED several days later, the infant was displaying measles symptoms and testing was sent to the lab for confirmation.
"Contact with a known measles case from Auckland was confirmed at this time."
Dr Jones said, as a general rule, a contact is considered to be someone who has been in the same room as a confirmed measles case (while the case was infectious) up to two hours after the case was there.
It usually takes 10 to 12 days from contact with someone with measles to the first symptoms. This is called the incubation period.
"A person who has measles is infectious from the very first symptoms to five days after they develop the measles rash," Jones said.
"The symptoms in the early stages of measles are the same as most other viral illnesses – including fever, runny nose, cough or red eyes – this means people can pass the virus on to others before it becomes apparent they have measles. That's why immunisation is so important."
The infant was discharged late on Sunday and is not considered contagious any more.
After health authorities confirmed the first case on Friday evening medical staff spoke to 124 people who had been in contact with the infant.
On Monday, a lab result confirmed a close contact of the infant - an adult - had contracted the disease and is in isolation at home.
Twenty-eight people who were in contact with the infant were in isolation at their homes as a precaution on Tuesday to try to prevent measles spreading.
Healthline reported a small number of calls at the weekend. Five phone calls were logged from Hawke's Bay people inquiring about the measles case.
Jones said no wider contact tracing was required following confirmation of the second case because the person shared the same family and community contacts as the first.
The first early symptoms of measles are fever, runny nose, sore red eyes and cough. After three to five days a red, blotchy rash appears on the face and head and then spreads down the body.
What to do if you suspect you, or a family member has measles?
If you believe you or a family member may have measles, please stay at home and phone your doctor to alert them of your symptoms and allow them to make arrangements to assess you safely and without infecting other people. You can also call Healthline for free advice on 0800 611-116.
Immunisation is very important: MMR Vaccine Protection
Two doses of the Measles, Mumps and Rubella (MMR) vaccine provides the most effective protection for yourself, your family and the wider community. After one dose of the MMR vaccine, about 95 per cent of people are protected from measles. After two doses, more than 99% people are protected.
In New Zealand, if you were born in 1969 or later, you can get the measles vaccine for free.
Older children and adults aged up to 50 years who have no documented evidence of vaccination against measles are recommended to get vaccinated.
Almost everyone aged 50 or older who have had measles as a child is immune. Ninety per cent of people in their 30s and 40s are immune. Teenagers and young adults are least likely to have been immunised as young children.
Visit: www.ourhealthhb.nz for all measles information, including translated Measles Fact