Then, using whip-like flagella, it swims through the stomach\u2019s mucus lining, using it like a blanket pulled overhead.<\/p>\n
Once through, it anchors to the stomach wall and stays, lives and multiplies.<\/p>\n
Most who carry it never know they have it, but for others it causes gastritis and ulcers.<\/p>\n
But most concerning, it is behind about three-quarters of stomach cancers worldwide.<\/p>\n
In 1994, the World Health Organisation (WHO) classified it as a group one carcinogen \u2013 the same category as tobacco and asbestos.<\/p>\n
It is a discriminate killer. <\/p>\n
Within the Kiwi population, it harms M\u0101ori and Pasifika at a far higher rate than Europeans.<\/p>\n
In 2020, the Ministry of Health\u2019s Cancer Action Plan put H. pylori on a shortlist of three cancers worth screening for, alongside lung and prostate.<\/p>\n
Despite the intention, six years later no programme exists, and current detection of H. pylori in Kiwis is described as \u201copportunistic\u201d.<\/p>\n
While New Zealand waits for a screening programme, this common and largely unknown bacterium survives the stomach\u2019s soupy acid, biding its time and, for some, killing.<\/p>\n
The nastiness of stomach cancer<\/p>\n
Poasa (Paul) Misipeka, 84, with his wife Nola, had half his stomach removed after being diagnosed with stomach cancer and is now slowly regaining his strength. Photo \/ Michael Craig<\/p>\n
Paul Misipeka, 84, reckons he\u2019s one of the lucky ones \u2013 see if you agree.<\/p>\n
In 2024, while tinkering in his beloved garden at his Warkworth home, he felt unwell.<\/p>\n
He struggled inside and fell asleep. His wife, Nola, was concerned and called an ambulance.<\/p>\n
This was Misipeka\u2019s first trip to hospital. He was checked out and sent home. Sadly, over the next weeks his condition worsened and he returned to hospital.<\/p>\n
\u201cI was really sick … I was vomiting blood,\u201d Misipeka, who hails from Niue, says.<\/p>\n
An endoscopy found a tumour in his stomach \u2013 he had cancer.<\/p>\n
As far as killer cancers go, stomach \u2013 or gastric \u2013 cancer is right up there.<\/p>\n
It is the fifth most common cancer in the world and the fifth most common cause of cancer death, Dr Cameron Schauer, a gastroenterologist and clinical senior lecturer at the University of Auckland, says.<\/p>\n
In New Zealand, about 400 people are diagnosed with stomach cancer each year and around 270 die from it, according to the Gut Cancer Foundation.<\/p>\n
\u201cAnd we don\u2019t pick it up early enough,\u201d he says. <\/p>\n
Schauer led a major study of gastric cancer covering 21 years of cases, analysing 1797 patients, the largest of its kind done in New Zealand.<\/p>\n
\u201cThe vast majority of cases that we had, in fact more than 84% of cases, were very advanced.\u201d<\/p>\n
Dr Cameron Schauer, of the University of Auckland, led the largest study of gastric cancer done in New Zealand.<\/p>\n
In his soon-to-be-published paper, 38% of all reports of gastric cancer reached stage 4, meaning the cancer had spread widely from the stomach by the time they were diagnosed. For M\u0101ori, the stage 4 figure was 44%.<\/p>\n
For those patients, average survival was under four months.<\/p>\n
M\u0101ori patients were diagnosed at an average age of 61 and Pasifika patients at 63, both about a decade younger than the New Zealand European average of 73.<\/p>\n
\u201cThis is a disease that is inequitable,\u201d Schauer says.<\/p>\n
\u201cIt\u2019s worse in M\u0101ori, Pacific and Asians, and is causing a huge amount of both morbidity and mortality in our population.\u201d<\/p>\n
And this is where Misipeka was lucky. When the cancer was found, it had not spread beyond his stomach, Misipeka\u2019s wife Nola says.<\/p>\n
Yet finding it was only a start. A later complication meant his stomach partly split open, needing emergency surgery. Ultimately, the tumour and about half of his stomach were removed.<\/p>\n
\u201cLuckily our doctor was very persistent,\u201d Nola says.<\/p>\n
Five months on, Misipeka is eating small portions, slowly regaining strength and easing back into a bit of gardening.<\/p>\n
\u201cI was pretty lucky that I went past 80s. A lot of young ones died a lot earlier.\u201d <\/p>\n
During her husband\u2019s ordeal, Nola recalls doctors mentioning \u201ca bug\u201d in his stomach and putting him on strong antibiotics.<\/p>\n
Misipeka had never heard of H. pylori. \u201cIt was a complete surprise,\u201d he says.<\/p>\n
Learning of the harm H. pylori can have, the couple are spreading the message, insisting their extended family get tested for the bacteria.<\/p>\n
Schauer says the most effective way to decrease stomach cancer rates is finding and eradicating the greatest cause \u2013 H. pylori infections \u2013 before cancer forms.<\/p>\n
\u201cIt requires a paradigm shift in thinking where we go from the ambulance at the bottom of the cliff waiting for patients to present with abdominal pain, bleeding, weight loss, inability to swallow, and shifting to a preventive mechanism where we know that we can prevent this from happening and prevent the cascade of inflammation and cancer.\u201d<\/p>\n
The need for a screening programme<\/p>\n
Whether a doctor finds an H. pylori infection in New Zealand comes down to ticking the right boxes and a bit of luck.<\/p>\n
Finding an infection should go like this: a patient turns up to their GP with symptoms like burning or pain in the upper abdomen, bloating, nausea or general stomach discomfort after meals \u2013 conditions labelled dyspepsia \u2013 and that\u2019s a tick in the check for H. pylori box.<\/p>\n
If the patient lives in northern New Zealand, is M\u0101ori, Pasifika or Asian, was born overseas where infection rates are high, has a family history of stomach cancer or lives in a crowded home, that\u2019s tick, tick and tick.<\/p>\n
A combination of those check marks means a doctor should request a test, usually a stool sample sent to a lab.<\/p>\n
If you have H. pylori but no symptoms, or don\u2019t fit the risk profile, then nobody\u2019s ticking boxes.<\/p>\n
Dr Andrea Teng, of the University of Otago, Wellington, co-leads New Zealand’s first population-wide study of H. pylori infection.<\/p>\n
And even patients who do have both symptoms and the risk factors get missed, says Dr Andrea Teng, a public health researcher at the University of Otago.<\/p>\n
\u201cM\u0101ori and Pacific, we know, have the highest rates of infection and are actually less likely to get tested than European and Asian groups. <\/p>\n
\u201dThe current approach is not reaching the groups that need it the most.\u201d<\/p>\n
Teng and a team of researchers have finished New Zealand\u2019s first population-wide survey of H. pylori infection, testing 1107 people aged 12 to 69.<\/p>\n
The results are preliminary but the pattern is clear. <\/p>\n
Blood tests, which show whether someone has ever been infected, found 48% of Pasifika participants and 15% of M\u0101ori participants had been, compared with 9% of European New Zealanders.<\/p>\n
Around 3% of people who carry H. pylori go on to develop stomach cancer, Teng says. <\/p>\n
Trials that followed people for about 10 years found treating those who tested positive cut stomach cancer by almost half.<\/p>\n
A real programme won\u2019t match a trial, because not everyone takes up an invitation or follows through.<\/p>\n
\u201cWe know that it\u2019s effective from the trials, so it\u2019s just implementation questions,\u201d she says.<\/p>\n
A working group hosted by the International Agency for Research on Cancer, part of the World Health Organisation, and including Teng, concluded that screen-and-treat programmes are cost-effective, and may even save money, in high-risk populations.<\/p>\n
Modelling based on 2011 data and prices found screening and treating for H. pylori would be good value.<\/p>\n
Aimed at M\u0101ori, it would cost about $12,000 for every extra year of healthy life gained. <\/p>\n
Offered to every adult aged 25 to 69, it would cost about $24,600. <\/p>\n
At the time of the modelling, the benchmark for good value was $45,000.<\/p>\n
\u201cIt\u2019s just really good value for money,\u201d Teng says.<\/p>\n
\u201cThat\u2019s where I think New Zealand needs to be \u2013 piloting an H. pylori screening programme.\u201d<\/p>\n
And Schauer agrees. <\/p>\n
\u201cWe have overwhelming evidence that this is an excellent thing to do, but it really has to be stratified based on risk,\u201d he says.<\/p>\n
\u201cI think we should really consider seriously a screen and treat programme for high-risk populations in New Zealand.\u201d<\/p>\n
And the Ministry of Health has long agreed, making such a programme one of three priorities in the 2020 Cancer Action Plan.<\/p>\n
So what is the hold-up?<\/p>\n
Dr Karen Bartholomew, Health NZ\u2019s director of health gain development, says a national programme has to be carefully considered, including research, the cost, impact on populations and whether any system is ready.<\/p>\n
Yet, the National Screening Advisory Committee, which Bartholomew chairs and advises on whether new national programmes go ahead, \u201chas not yet reviewed H. pylori screening for gastric cancer\u201d.<\/p>\n
\u201cIt is on the list for future consideration,\u201d Bartholomew says. <\/p>\n
Health NZ is running feasibility studies on adding H. pylori testing to bowel screening, she says.<\/p>\n
The Cancer Action Plan was updated in 2026 and has set one dated H. pylori goal \u2013 make a plan to design a pilot scheme by 2027.<\/p>\n
New Zealand\u2019s delay isn\u2019t unusual. <\/p>\n
The international agency Teng contributed to has recommended countries consider screening high-risk groups since 2014, and a report in the New England Journal of Medicine this year found implementation has met with \u201chesitation and limited action\u201d. <\/p>\n
It counts just three population-level programmes worldwide.<\/p>\n
Schauer believes New Zealand should mirror others.<\/p>\n
\u201cIn New Zealand, we like to have ingenuity but I think what we should do in this instance is see if we can just copy and translocate what\u2019s worked very well in other countries.\u201d<\/p>\n
Killing H. pylori \u2013 it\u2019s getting tricky<\/p>\n
Nobel laureate Barry Marshall, who drank a broth of H. pylori in 1984 to prove it causes stomach disease. Photo \/ Chen Wen, China News Service via Getty Images<\/p>\n
It took a \u201ccrazy\u201d scientist to prove the link between H. pylori and stomach diseases.<\/p>\n
Doctors used to believe nothing could survive the stomach\u2019s acid. Gastritis and ulcers were blamed on stress, spicy food, too much acid.<\/p>\n
Research by Australian physicians Robin Warren and Barry Marshall started linking the conditions to bacteria discovered living in the stomach.<\/p>\n
In 1984, after experts dismissed the research and animal testing failed, Marshall decided to become the petri dish and drank a broth swimming in H. pylori.<\/p>\n
Within days, he was vomiting, with gastritis spreading through a stomach that had been clear a week before.<\/p>\n
In 2005, Marshall and Warren won the Nobel Prize in Medicine for their work.<\/p>\n
\u201cPeople thought he [Marshall] was a bit crazy,\u201d says Dr Tom Mules, a gastroenterologist at the Malaghan Institute.<\/p>\n
Nearly everyone who carries H. pylori caught it by their 10th birthday.<\/p>\n
\u201cThis is acquired typically in childhood, and typically from your family members you\u2019re living with,\u201d Mules says.<\/p>\n
There are two main strains of the bacterium \u2013 a Western strain and a more aggressively cancer-driving East Asian strain, he says.<\/p>\n
Because it\u2019s passed down within families, a strain tends to stay within the same ethnic communities for generations. M\u0101ori and Pasifika populations are thought more often to carry the East Asian version, a possible factor behind New Zealand\u2019s higher gastric cancer rates among those groups.<\/p>\n
The standard Kiwi treatment to eliminate H. pylori is called triple therapy \u2013 taking two broad-spectrum antibiotics and an acid-suppressing drug for two weeks. The treatment works for most, with an 85% or greater chance of clearing infection.<\/p>\n
Dr Tom Mules, a gastroenterologist and researcher at the Malaghan Institute, is working on an mRNA vaccine for H. pylori. Photo \/ Supplied <\/p>\n
However, H. pylori is growing antibiotic resistance.<\/p>\n
\u201cIf we look at Clarithromycin, which is the main antibiotic that New Zealand uses to treat Helicobacter pylori, our resistance rates are probably sitting around maybe the 10% mark,\u201d Mules says.<\/p>\n
\u201cIf you go to some countries in the world, particularly Europe, like France, it\u2019s sitting more around 40% and so they\u2019ve abandoned that therapy completely.\u201d<\/p>\n
Mules, an expert in H. pylori\u2019s biology, is racing to offset growing antibiotic resistance.<\/p>\n
At the Malaghan Institute, they have developed a molecular test that can detect resistance genes straight from a patient\u2019s stool sample, meaning doctors could prescribe the right antibiotic the first time, rather than guessing, he says.<\/p>\n
Mules is also chasing the \u201choly grail\u201d \u2013 a vaccine.<\/p>\n
\u201cBecause we know what causes the stomach cancer, why can\u2019t we prevent that cause?\u201d he says. <\/p>\n
\u201cKind of in the same way that we do with cervical cancer and HPV.\u201d<\/p>\n
Development won\u2019t be simple \u2013 30 years of attempts by researchers worldwide have failed to deliver \u2013 so far.<\/p>\n
A vaccine, if it comes, would protect the next generation. For the people carrying H. pylori now, the answer is to find it and treat it.<\/p>\n
Misipeka\u2019s advice is simple.<\/p>\n
\u201cJust go to the doctor and get all checked out,\u201d he says. <\/p>\n
\u201cIf you leave it too long … it will get worse and it\u2019s harder to fix.\u201d<\/p>\n
Mike Scott is a senior journalist at the Herald. His work spans writing, photography and video and he has won numerous journalism awards, including Videographer of the Year and Best Documentary. He has worked in media for more than 25 years, producing stories across New Zealand and internationally.<\/p>\n