An Auckland ambulance officer's online warning to vaccinate against measles has been shared thousands of times on Facebook as authorities warn that confirmed cases have reached 635 so far this year.

Brendan Peat posted the warning in the early hours of Saturday morning after transporting another measles patient to Middlemore Hospital, writing: "Time for a plug as the outbreak slowly turns towards an epidemic".

Peat begged Kiwis to "please trust science, and vaccinate not only kids but adults too against such an easily preventable disease which is proven safe and effective."

Peat also claimed that Middlemore Hospital has switched off the air conditioning in their "kids' department" in order to prevent the virus spreading.

Counties Manukau Health told the Herald that they are currently accommodating children with measles or suspected of having measles in isolated, negative pressure rooms but that the air conditioning has not been turned off.

A spokesperson told the Herald: "The wards are still fully air-conditioned however the air handlers have been set to vent all of the air externally without recirculation or heat recovery, which is the normal process in the hospital."

Peat's warning comes as another 19 Aucklanders have been infected with measles in the past three days, with fears looming that New Zealand is verging closer to losing its World Health Organization (WHO) "elimination" status.

Auckland Regional Public Health Service (ARPHS) revealed today that Auckland has seen 635 confirmed cases of measles this year, with 435 in Counties Manukau alone.

Cases have been reported across Auckland. Photo / ARPHS

ARPHS stresses that the only way to stop the spread of measles is to ensure everyone living in New Zealand has had at least 1 MMR vaccination. Children can receive the vaccination at 12 months and at 4 years, though infants 6 months and older can receive the vaccination if travelling to countries with measles outbreaks.

Peat wouldn't speak to the Herald today but his stance is backed by St John, with Dr Tony Smith, St John Medical Director, telling the Herald that "St John strongly supports vaccination as the most effective way of reducing the considerable harm caused by preventable infectious diseases, including measles."

Experts warn the spread will likely continue unless nationwide immunisation rates improve.

"Unless New Zealand can do more to improve our community immunity, to stop these cases continuing to spread to others, we are at significant risk of losing our elimination status," Immunisation Advisory Centre director and GP Dr Nikki Turner told the Herald earlier this month.

Turner said it would take several years to get that status back, which was a "huge concern" as further outbreaks would be likely.

New Zealand gained the WHO measles elimination status for the first time in 2017 after proving there had been no outbreak for more than three years. The WHO aims for 95 per cent immunity coverage nationwide. However, New Zealand currently only has 91 per cent, with timely infant immunisation rates as low as 61 per cent in some regions.

Nine out of 10 people who contracted measles this year had not been vaccinated or didn't know their vaccination status, figures by Government agency, the Institute of Environmental Science and Research figures, showed.

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