Auckland University senior lecturer and director of research at the Immunisation Advisory Centre, Dr Helen Petousis-Harris (file photo).

A phony anti-vaccination film is blamed for an alarming drop in immunisation rates.

Further, experts say it is being peddled by deluded activists burdened by a false sense of superiority.

The pseudo-documentary Vaxxed: From Cover-Up to Catastrophe toured New Zealand early this year and is based on debunked research linking the measles, mumps and rubella vaccine (MMR) and autism.

KELLY HODEL /STUFF

Dr Felicity Dumble, director of public health for the Waikato DHB, said health officials must urgently address the drop in immunisation rates.

New immunisation figures show a drop in coverage rates in Waikato, Auckland, Northland and Waitemata, prompting experts to label those pushing the anti-vaccination message as dangerous and delusional.

Latest Waikato DHB figures show immunisation rates for young Maori has crashed in the past six months, from 91 per cent coverage to 82 per cent.

STUFF

Northland GP Dr Lance O'Sullivan said anti-immunisation rhetoric has killed children around the world (file photo).

DHB staff will meet with Health Ministry officials in November to brainstorm ways to reverse the decline.

Felicity Dumble, Waikato DHB director of public health, said fallout from the Vaxxed film had contributed to the decline in vaccination rates.

"Anecdotally, it does appear to have had an impact in terms of what we're seeing, not just in the Waikato, but nationally," Dumble said.

"It's extremely disappointing and the concern is that we will see more outbreaks of these preventable diseases like we have seen with measles and mumps because of misinformation that is being spread in the community.

"People don't often realise that these diseases can be fatal. With our recent outbreak of measles, we saw multiple hospitalisations."

Mumps cases were also recorded in Waikato this winter, the first in the region since 2012.

Mumps outbreaks were also recorded in other parts of the country, including Palmerston North, Dunedin, and Auckland. The outbreaks were especially prevalent among young people.

Dumble said people aged 10 to 29 had relatively poor immunisation coverage, a consequence of fallout from the retracted 1998 research paper linking the MMR vaccine to autism.

The study's author, disgraced UK doctor Andrew Wakefield, directed Vaxxed.

During one screening of Vaxxed, Northland GP Dr Lance O'Sullivan took to the stage to slam the film and said anti-immunisation proponents had killed children around the world.

Auckland University vaccinologist Dr Helen Petousis-Harris said the Vaxxed film had had a direct and negative impact on immunisation rates across several DHBs.

Those actively promoting anti-vaccination rhetoric were often people of low ability burdened by a false sense of superiority, she said.

The condition is known as the Dunning-Kruger effect.

"They mistake their inadequacies for knowledge," Petousis-Harris said.

"You see that when you look at social media streams. You can see this absolute confidence in what they believe they know."

Petousis-Harris said the small group of anti-vaxxers were different to parents hesitant about getting their children vaccinated.

It was important health professionals acknowledge and address parents' concerns about vaccination rather than dismiss them.

Correcting scientific falsehoods started with education and the teaching of critical thinking, but did take time, Petousis-Harris said.

"A lie travels around the world in a nanosecond and when the truth comes limping after it, it's sort of too late.

"These people [anti-vaxxers] pose a risk to the public's health because they are actively trying to derail it. If we leave it and do nothing ... their activities will have a direct effect on public health because confidence in vaccines go down, people don't vaccinate, you get more diseases, it's pretty straightforward. That's what happened after Andrew Wakefield: They had measles and they had deaths in the UK."

Waikato University senior biology lecturer Dr Alison Campbell said it was easy for people lacking critical thinking skills to willingly accept what they read on the internet as the truth.

Campbell said it was wrong to dismiss anti-vaxxers as stupid, but excessive self-confidence is a factor.

"They end up doing their research on Google university and they end up thinking they are right and they have the right information because there's a very strong feedback loop within the closed chamber that they become a part of," Campbell said.

She said it was vital the views of anti-vaxxers are challenged by health professionals and academics.

"We need to keep the commonsense, reasoned, factual response there to match the unreasonable, non-commonsense, non-factual response."

Waikato DHB executive Julie Wilson said that as well as the screening of Vaxxed, a busy winter season and difficulties contacting transient families had also contributed to a decline in immunisation rates.

Wilson said the Waikato DHB needs to work with primary care providers and the Health Ministry to devise a plan to lift vaccination rates.

Any barriers to vaccination must be identified and removed.

"We need to find a way to move forward or actually look at whether we do a significant change in approach," Wilson said.

The DHB was waiting on the Health Ministry's chief child health adviser to help them come up with an action plan.

Health Minister David Clark didn't respond to media requests for comment.

- Stuff