Explainer: It’s a disease that thousands of New Zealanders may have but not even be aware of.

Hepatitis B can lurk in the body for years, and ultimately end up causing deadly conditions like liver cancer or cirrhosis.

Helen Quirke, an assistant principal and Kaiarataki o te Ao Māori at Greerton Village School in Tauranga, had no idea she was carrying hepatitis B until a test when she was pregnant with her first child. She had no symptoms, no indication she was sick.

“I wasn’t aware of anything at that point, so it was quite a shock when I found out.”

She’s now been living with it for more than 20 years.

She’s not alone – most people who have hepatitis B don’t know it, the Hepatitis Foundation of New Zealand says.

It can only be diagnosed through a blood test, said Dr Chris Moyes, the foundation’s medical director.

It’s the leading cause of liver cancer in Aotearoa, and with World Hepatitis Awareness Day on Tuesday, the foundation is hoping to spread the word that testing and support is available for what it calls a “silent epidemic”.

Here’s what you need to know about hepatitis B – and how to know if you might be carrying the virus.

What is hepatitis B?

Hepatitis is an inflammation of the liver and there are various kinds that can cause illness, ranging from short and unpleasant to life-altering conditions.

Hepatitis B is a highly contagious viral infection that can cause acute short-term illness or chronic disease that can linger, hidden for years.

It can be transmitted by contact with infected blood or bodily fluids or through mother to baby at birth. Almost all new chronic infections come in early childhood, through birth or close contact with a carrier. Most babies can’t clear the virus from their liver and it stays there the rest of their lives.

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The good news is, there is a vaccine that can prevent that. Since 1988, it’s been administered routinely to children in New Zealand starting at 6 weeks old, and the foundation said that has effectively eliminated childhood transmission.

But the Hepatitis Foundation said chronic hepatitis B infection is still endemic in New Zealand among those who were never vaccinated, affecting an estimated 94,000 adults – with Māori, Pasifika, Chinese and Southeast Asian New Zealanders disproportionately affected.

The World Health Organization (WHO) said an estimated 240 million people were living with chronic hepatitis B as of 2024, and there were an estimated more than 1 million deaths – mostly from cirrhosis of the liver or liver cancer.

WHO’s Western Pacific region – which includes China, New Zealand, Australia and Pacific Islands – has the world’s highest rate of hepatitis B.

Until a few years ago, all Quirke had to do was have regular blood testing every six months to see if the virus was spreading and check her liver health. Then, one visit turned up worrying results.

“In this particular visit, it had elevated quite a lot. We had a conversation around potentially what that would mean.”

She now has to take antiviral medicine, but it’s helped bring the levels down.

“There’s a commitment required, once you start” treatment, she said.

“You just don’t know what the virus is going to do. At the moment I’m really fortunate, it’s suppressed, but what could happen if it decided to take its own course?”

An image of the hepatitis B virus from an electron microscope. Photo / Getty Images

Is there treatment?

If you have chronic hepatitis B, you will currently require some kind of life-long monitoring and blood tests.

If your liver is damaged, actively inflamed or you have a high viral load, you may have to take daily antiviral medicine like Quirke does.

Antiviral treatment is fully funded for all New Zealanders with chronic hepatitis B.

The Hepatitis Foundation provides a long-term monitoring programme that includes access to community nurses, testing and treatment.

“If someone suspects that they have hepatitis B we can organise a free test for them at a lab testing place or one of our community nurses can take the test if it works,” a spokesperson for the foundation said.

Researchers are trying to find a cure as new medicines are developed, with the goal of finding a way to keep the virus under control without ongoing use of medicine.

Hepatitis B-related liver cancer hasn’t decreased here despite the vaccine’s introduction – which reflects an ageing population who were infected before 1988, and migration to New Zealand of adults from countries with higher rates of infection.

Figures from Auckland City Hospital show a steady rise in reported cases through much of the last 15 years.

Who is most likely to have it?

The Hepatitis Foundation lists major risk factors:

• You are over 35 years of age
• You are of Māori, Pacific or Asian ethnicity
• Your mother or close family member has hepatitis B
• You live with someone who has hepatitis B
• You were born outside New Zealand, in a high-risk country
• Have had unprotected sex with a person living with hepatitis
• Have ever injected drugs
• Have received a tattoo using unsterilised equipment

Quirke also has an older brother who had been diagnosed years ago with hepatitis B – a family link can be a key indicator the virus could be in the wider whānau.

Why does it affect certain groups more than others?

Many of the countries where hepatitis B is still high risk don’t have childhood vaccination programmes or took longer to introduce them.

“All peoples who historically populated the Pacific Rim countries have high hepatitis B infection rates – the virus has been around for thousands of years,” Moyes said.

“High-risk countries include the Pacific Islands, Southeast Asia and sub-Saharan Africa.”

A 2018 report by the foundation cited research that in New Zealand it was highest in those of Tongan ethnicity (13%), Chinese (9%), Niuean (9%), Southeast Asian (9%), Cook Islands (7%) and Māori (6%).

“Particularly for Māori, Pasifika and our Asian community, it’s massive and I think that there’s thousands of people that potentially have the virus and may not be aware,” Quirke said.

She said there may also be barriers for people thinking about getting checked.

“It could be the cost of the GP, it could be access to the GP, even getting an appointment nowadays is really, really hard.”

As chronic hepatitis B is more likely to turn up in older people, that can also create a barrier.

Quirke said that earlier generations weren’t as open to talking about personal health matters, but that is starting to change.

“For us it’s a lot more normal to have a conversation around, you know, this is what I have, or making sure that we get checked and keeping an eye on each other as well, just checking in on each other’s health.”

The Hepatitis Foundation would like to see a national “Test and Treat” programme that it says could save thousands of lives and reduce costs.

It would “ideally diagnose by simple finger-prick test with immediate referral for further tests and assessment in positive cases”, Moyes said.

An investment in broader testing would target at-risk communities and scale up the Hepatitis Foundation’s existing work.

The foundation says it offers “the largest community-based programme in the world and is widely regarded as the best model for countries with endemic chronic hepatitis B infection”.

But funding hasn’t kept up with demand for the nonprofit.

What can you do if you suspect you might be carrying it?

Hepatitis B often has no symptoms – the acute version of the condition, which has a shorter duration, can cause abdominal pain, fatigue, dark urine and jaundice.

But chronic hepatitis B can be more subtle – some people may have ongoing tiredness and mild symptoms of the acute form, according to the American medical researcher Mayo Clinic, but many may have none at all.

It can result in a ticking “time bomb” slowly damaging the liver until it’s too late.

If you meet some of the conditions above, have never been vaccinated or have a family history, you can talk to your GP or contact the foundation for more information.

Knowing your family medical history and childhood vaccination information can help, Quirke said.

“Unless you know that perhaps there’s somebody in your whānau who has hepatitis B, you wouldn’t necessarily know to go and get that screening.

“I’ve been really fortunate with the care that I’ve had.”

You can contact the Hepatitis Foundation at 0800 33 20 10 or via their website.

How difficult is living with it?

Chronic hepatitis B can be managed by taking antiviral medications including Entecavir or Tenofovir and regular blood tests and monitoring, Moyes said.

“Both of these drugs are very safe and side effects are uncommon, but they need to be taken long term.

“Infected patients also require regular surveillance to detect if liver damage or liver cancer develops.”

There’s still a lot of stigma around a diagnosis of chronic hepatitis B, the foundation says, which can lead to isolation and a reluctance to get proper treatment.

Living with hepatitis B requires you to be more aware of your health, Quirke said.

“I’ve got to take this pill every day for the remainder of my life [or] until such time perhaps that there is a cure,” she said.

For people living far from medical care or unable to easily get to it, monitoring can be difficult.

“The six-monthly blood test, for some people, might also be a bit of a challenge.”

Patients should avoid alcohol and smoking and generally keep to a healthy diet.

“Liver damage may be aggravated by excessive use of alcohol or by fatty liver [usually associated with obesity or diabetes],” Moyes said.

Quirke is also a qualified naturopath and said “education has been my life”.

“It’s all about balance,” she said, “just a whole general healthy approach to life, good nutrition, good sleep, stress levels, exercise – all of those things which I really feel like I think about more so now than I would have prior to getting the diagnosis.”

Quirke was 29 years old when she learned she had hepatitis B. She recently turned 50.

Her focus is on “making sure that hopefully I’m around for a long time, that I’m here as a nan, and get to see my mokopuna”.

“I think it definitely causes you to reflect on your own lifestyle. Looking after your tamariki, as they all have to get vaccinated at birth. Thinking about your wider whānau and checking in.

“... Because I didn’t know that I even had it so potentially there’s a lot more others that may not even know that they carry it.”

  This story was first published on rnz.co.nz