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11 Aug 2020

Superinfection: Testing and Treating Hepatitis B and D in Kiribati

By Kathy Jackson, Section Head of Molecular Microbiology at the Doherty Institute

As new research reveals the prevalence and characterisation of hepatitis B and D infections in Kiribati, Kathy Jackson shares her experiences of testing and treating hepatitis in the country.

The Republic of Kiribati is a remote country in the central Pacific Ocean, a picturesque island nation that’s united across 33 coral atolls. Along with its unique beauty, the low-to-middle income country is distinctive in its high rates of hepatitis infection, with historical reports indicating that hepatitis B (HBV) and hepatitis D (HDV) infections are highly endemic amongst the population.

I travelled to the country’s capital, Tarawa, in 2018 with my colleague’s Dr Po-Lin Chan (WHO WPRO regional Office), Dr Alice Lee (Director, Hepatitis B Free) and Dr David Hilmers (Professor, Baylor College of Medicine, Houston). Our goal was to establish a liver clinic, assess laboratory capacity for hepatitis testing, and to assess individuals for antiviral therapy. The invitation came from the Ministry of Health as a source of Tenofovir, a medication used to treat chronic HBV, had become available for patients in Kiribati – an unmissable opportunity for people living with the disease.

Our intensive three day visit involved hepatitis training and education sessions, an on-site laboratory capacity assessment and liaising with hospital staff and Ministry Officials. Two liver clinics were conducted with 68 patients in attendance, and 12 patients identified for immediate Tenofovir treatment. The remaining patients would be monitored every six months for worsening of their liver disease.

While the levels of HBV and HDV infection were relatively unknown, the liver clinics revealed the extent of the morbidity and mortality to hepatitis across the capital. We heard stories from patients that described the deaths of family members with liver disease-related symptoms; it became clear that it was essential to learn more about the drivers of HBV and HDV across the island nation.

A traditional house in Fanning Island, Kiribati
A traditional house in Fanning Island, Kiribati

Hepatitis D: The satellite infection

Our research, published this month in the Journal of Clinical Virology, discusses the prevalence and the characterisation of HBV and HDV co-infection in Kiribati. Through obtaining and screening sera from 219 patients, we found that of the 10 - 15 percent of residents living with chronic HBV in the country, 40 percent also have a co-existing HDV infection. This is a staggeringly high percentage when we consider the global rates of co-infection, which are thought to be around five percent.

HDV is satellite virus and must co-exist with hepatitis B – it cannot live without it - and it makes the disease’s symptoms far more serious. Coinfection usually manifests as a ‘superinfection’ because it infects people with established chronic hepatitis B and it makes the impacts of HBV considerably worse. Coinfection can cause more rapidly progressing disease, higher rates of cirrhosis, hepatocellular carcinoma and fulminant (sudden and severe) hepatitis.

Typically, a patient with chronic hepatitis B acquires HDV in their second or third decade of life. Our research in Kiribati, however, found a 4 year old boy with HBV and HDV co-infection. This is extremely rare. It suggests that he acquired HDV from his mother during birth or not long afterwards. He was very unwell by the time he came to the clinic with a swollen liver, which is a sign of hepatomegaly. His mother was cirrhotic and a candidate to begin treatment immediately.

Our research found that much of Kiribati’s population living with hepatitis B acquired the infection as a child, and maternal to child transmission was identified as a contributing factor, along with transmission between siblings.

Our research also suggested that cultural practices play a role in the high rates of HBV and HDV. For those with HBV and exposed to HDV as an adult, they can acquire the co-infection through practices such as tattooing and ear-piercing. We also identified unsafe dental and healthcare practices as potential driving factors that could be contributing to the spread.

Teaching, testing and treatment

The high rates of hepatitis co-infection complicates things for people in Kiribati. While there are newly licensed treatments for combatting HDV, they are not easily available – particularly not in a remote island nation. At present, the best option that can be offered to patients in Kiribati is to test and treat HBV infection.

I went back to Kiribati in January this year to try and introduce HBV viral load testing on the GeneXpert, which acts like a point of care platform for testing different viruses and bacteria. Kiribati has a GeneXpert which they use for the identification of tuberculosis and HIV. With the HBV assay now available, I brought several cartridges along with me to show the scientists how they can use them in their laboratory.

Due to the virus’s prevalence, we didn’t have to look very far to find patients to work with for the testing; some of the scientists we were working with had HBV and were able and willing to give blood. We ran the viral load there and then and had a result within the hour.

Since then, our team at the Doherty Institute’s Victorian Infectious Diseases Reference Laboratory (VIDRL) has tested more than one thousand samples from Kiribati. It’s been able to give the local health authorities an idea of the prevalence of HBV and HDV co-infection in the country. It offers details on the viral load and whether patients have signs of liver damage, which provides information on which phase of infection the patient is in and whether they need to access treatment.

Following the original visit in 2018, a hepatitis clinic has been set up in Tarawa and more than one hundred people are on treatment. Our goal is to extend this work to the outer islands of Kiribati. We also want to eliminate mother to child transmission by treating mothers with high viral loads with Tenofovir while they're pregnant. Now that Tenofovir is available in-country, this is possible.

HBV is also highly prevalent in Kiribati’s neighbouring countries, including Papua New Guinea, Tonga, Vanuatu and Fiji. My great hope is to roll out this work further in order to help people living with hepatitis B across the Pacific Ocean.