Forty-five years after Mario Rizzetto discovered the hepatitis D virus (also known as HDV or hepatitis delta), scientists and advocates met for the first ever Delta Cure Meeting to discuss new scientific trends and global advocacy efforts to eliminate this difficult-to-treat disease. This conference included topics ranging from HDV’s global prevalence to new diagnostic methods, and the need for specific and improved efforts to fight this virus.
During the Delta Cure Meeting, scientists called for new global strategies to find people living with HDV and have prompted the World Health Organization (WHO) to update their screening guidelines to include HDV tests for all people living with hepatitis B (people who are HBsAg-positive).
Unfortunately, some barriers continue to stand in the way of making this call to action a reality. Dr. Meg Doherty, the Director of Global HIV, Hepatitis, and STI Programmes at the WHO, stated in a recent Healio article that the WHO does not have any prevention recommendations that are specific to HDV. However, the WHO is developing updated guidance for HDV testing, diagnosis, and treatment as a part of hepatitis B (HBV)-focused elimination efforts.
While some initial progress has been made, (such as the inclusion of HDV in the 2022-2030 Global Health Sector strategies, which aim to increase knowledge about infections like HIV and viral hepatitis to create effective responses to and advance elimination efforts for these diseases), there is a need to expand elimination strategies to include HDV more broadly. The lack of robust inclusion of HDV disregards people who are currently living with HBV and are at the highest risk of HDV exposure and acquisition. People who have been diagnosed with HDV are overlooked as linkage to appropriate care, diagnostics and treatments (which are important for people living with HDV to stay healthy) continues to be out of reach for many. One of the major challenges with HDV is also the lack of testing and surveillance to identify those individuals living with delta and to understand the true burden of the disease.
The WHO affirms that HDV elimination efforts must start with raising awareness of the virus and increasing advocacy efforts. The scientists at the Delta Cure Meeting are doing just that. Here are some solutions that scientists and researchers have identified to address the challenges surrounding HDV elimination:
Barrier: Overly complicated screening guidelines present a major barrier to the elimination of HDV. It was only in March 2023 that the Centers for Disease Control and Prevention (CDC) introduced new guidelines recommending universal HBV screening for all adults in the United States. A recommendation for universal HDV reflex testing (automatic testing for HDV when one tests positive for HBV) for all individuals living with HBV has still not been implemented in the US. Additionally, the American Association for the Study of Liver Diseases (AASLD) has screening guidelines for HDV that are still risk-based, meaning that only people who have certain risk factors are recommended to be tested for HDV (high-risk groups include people who inject drugs and men who have sex with men, among others). Conversely, the European Association for the Study of the Liver (EASL) and the Asian-Pacific Association for the Study of the Liver (APASL) have moved away from risk-based screening. Both EASL and APASL recommend that providers perform the HDV antibody total (anti-HDV total) test in all HBsAg-positive patients to identify whether someone has recovered from or is currently infected with delta antibodies (Palom et al., 2022; Hepatitis B Foundation, 2023).
Risk-based screening burdens both providers and patients alike. As part of risk-based testing, providers must ask questions about risk factors that are not necessarily part of a regular health screening and must know which factors indicate a need for HDV testing. Providers are often hesitant to ask their patients these questions, as talking about risk factors can be uncomfortable and overwhelming. But if providers do not ask, then the patient must know their own risk factors and ask for the test themselves (which can be very uncomfortable). A guideline to test everyone who is positive for hepatitis B (HBsAg-positive) for HDV would eliminate this confusion and hesitation. In light of this barrier, and the fact that risk-based testing is not evidence-based, the Hepatitis B Foundation recommends that all people living with HBV ask their doctors about getting tested for hepatitis delta.
Call to Action: Introduce new screening guidelines, including screening all adults who are HBsAg-positive for HDV. As the US does not have universal HDV screening guidelines, people who test positive for the hepatitis B surface antigen (HBsAg) but do not fall into a “high risk” category are not recommended to be screened for HDV, so they may be living with hepatitis delta and unaware of their infection. This puts these individuals at a much higher risk of having unmanaged hepatitis delta and developing liver cirrhosis or other advanced liver diseases at a more rapid pace. HBV is also already significantly underdiagnosed in the US and, as Dr. Nancy Reau neatly summarized “If you aren’t thinking about B, you’re not thinking about D.”
Barrier: HDV is not a nationally notifiable or reportable condition in the United States. This means that healthcare providers are not required to report cases of HDV to local and state health departments or to the CDC. Because of this, the actual number of people living with HDV in the US remains underestimated, and without accurate prevalence data, prioritization of this neglected disease is made all the more difficult.
Call to Action: Make HDV a reportable and notifiable disease in the US and beyond. Dr. Doherty of the WHO agrees that efforts to identify the populations most at risk for HDV are needed in the fight for HDV elimination, and specifically mentions the need for epidemiological surveys (different study designs of various sizes to better understand the burden of disease). A new survey method was discussed at the 2022 Delta Cure Meeting by Dr. Saeed Hamid in his presentation, “Epidemiology of HDV: From Low to High Endemic Countries.” Dr. Hamid called for new national surveys to be distributed to people with advanced liver disease because this population is one in which HDV is most likely to be found. He believes this monitoring method can be used in any country to advance elimination efforts.
Barrier: There are currently no standard HDV diagnosis methods, which makes HDV elimination very difficult to achieve. Professor Maurizia Brunetto, who presented “Diagnosis of HDV: Clinical Virology and New HBV Biomarkers,” explained that there is likely an underestimation of HDV infection in general, due to misdiagnosis (when someone is incorrectly diagnosed) and challenges accessing the diagnostic testing for hepatitis delta. When Dr. Doherty of the WHO was asked about what needs to be done to improve HDV elimination efforts (specifically in the US), she mentioned improving diagnostic testing tools.
Call to Action: Simplify testing and introduce point-of-care testing to increase HDV detection and diagnosis. Prof. Brunetto explained that point-of-care testing (getting rapid results within 20 minutes of being tested rather than waiting for up to 48 hours for results of a traditional blood test) can improve overall HDV diagnostics around the world. She believes it is especially important to introduce point-of-care testing in countries with less developed medical infrastructure. Having this point-of-care testing method will be easier to maintain and can identify people living with HDV earlier and link them to treatment before their disease becomes more severe. Dr. Stephen Urban, who led the discovery and creation of the first ever drug for HDV (bulevirtide), has been developing a point-of-care test to find delta antibodies from one single drop of blood. While only in the experimental phase, Dr. Urban and colleagues have published two journal articles that provide evidence for the test’s potential effectiveness in identifying people living with HDV (Lempp et al., 2021). While still more than two years away from using this method at a larger scale, Dr. Urban believes that this method can lead to faster HDV diagnostics.
As new HBV screening guidelines are introduced and new diagnostic tools are being developed, we have to advocate for universal HDV screening in individuals with hepatitis B by raising public awareness of the importance of screening and raising the voices of people who are living with HDV around the world.
References
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Centers for Disease Control and Prevention [CDC]. (n.d.). Interpretation of hepatitis B serologic test results [Fact Sheet]. U.S. Department of Health & Human Services. https://www.cdc.gov/hepatitis/hbv/pdfs/serologicchartv8.pdf
CDC. (2022). Nationally notifiable diseases. U.S. Department of Health & Human Services. https://www.cdc.gov/healthywater/statistics/surveillance/notifiable.html
CDC. (2023, March 10). Screening and testing for hepatitis B virus infection: CDC recommendations — United States, 2023. MMWR | Recommendations and Reports, 72(1);1–25. https://www.cdc.gov/mmwr/volumes/72/rr/rr7201a1.htm?s_cid=rr7201a1_w
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Palom, A., Rando-Segura, A., Vico, J., Pacin, B., Vargas, E., Barreira-Diaz, A., Rodriguez-Frias, F., Riveiro-Barciela, M., & Esteban, R. (2022, October). Implementation of anti-HDV reflex testing among HBsAg-positive individuals increases testing for hepatitis D. Journal of Hepatology, 4(10), 100547. https://doi.org/10.1016/j.jhepr.2022.100547
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