The total number of confirmed measles cases in Auckland has risen to 302, with an average of eight people a day being diagnosed with the disease.
The outbreak took hold of New Zealand at the start of the year, with cases of the illness rising from a handful in Waikato and Bay of Plenty in January, to about 40 in Canterbury through March.
The disease surfaced in Auckland in late March and has since been worst felt in South Auckland, with over half of all cases - 58 per cent - recorded in Counties Manukau DHB.
Waitemata DHB has had 85 cases, while Auckland DHB is at 41 confirmed cases.
Auckland Regional Public Health Service medicine specialist Dr Maria Poynter said the number of people diagnosed with the illness continues to grow, with the average number of cases each day rising from six a day in July, and three a day in June.
This week has averaged eight cases a day, she said.
Figures show that most cases in Auckland are in children under 5, with 118 recorded cases, and those aged 15 – 29 years are next in number, with 107.
There have been 36 cases in children aged 5 – 14 and 41 cases in those aged 29 and over.
Children are supposed to get vaccinations for measles, mumps and rubella (MMR) at 15 months and again at 4. Getting both jabs gives them a 99 per cent chance of lifetime immunity, and even one jab provides 95 per cent immunity.
But in order to protect those most at risk, ARPHS has changed the immunisation schedule to allow babies to get their first vaccination at 12 months.
Anyone aged 50 or over does not need to be vaccinated. They are considered to be immune already because measles was widespread in their childhood.
In terms of ethnicity, over 40 per cent of cases have been in Pacific people, with 132 cases.
A quarter of cases were in Maori, with 78, and in Pakeha there have been 92 cases.
The gender ratio is much more even, with 44 per cent of cases being female, and 56 per cent male.
Judging by these figures, the number of people confirmed to have measles is likely to be the highest since 2011 - when there were 597 cases.
Despite this earlier outbreak, in 2017, the World Health Organisation verified that New Zealand had "eliminated" endemic measles.
This meant no measles cases had originated in New Zealand, rather they had all been brought in from overseas.
Environmental Science and Research (ESR) public health physician Dr Jill Sherwood said the only thing which could stop the spread was higher vaccination rates.
"The pattern is clear. Outbreaks start when measles is brought into the country by someone who has travelled in from overseas. The virus then spreads to others in the community because our vaccination rates are simply not high enough to prevent disease spread," she said.
Anyone who has not had two documented doses of MMR vaccine is eligible for free vaccines.
Measles is one of the most contagious viruses, and anyone who is not immune and who has been in the same space as someone with the illness is at risk of becoming unwell.
The disease is spread easily through the air via coughing and sneezing.
Once a person contracts measles, it can be 10 to 14 days before they begin seeing symptoms.
Such symptoms include a high fever, runny nose, cough and sore red eyes. A few days later a rash starts on the face and neck, and then spreads to the rest of the body.
• If you are concerned about measles call Healthline on 0800 611 116 or call your GP. Please do not just turn up to your GP, after hours or emergency department as you could potentially infect others.