Hepatitis B: Understanding the Virus, Symptoms, and Global Prevention Efforts
- Share via
Hepatitis B is a serious liver disease caused by the hepatitis B virus (HBV), which is a small DNA virus from the Hepadnaviridae family. If someone has this infection for a long time, it can lead to ongoing liver damage, and in some cases, it may even result in death. In 2019, about 296 million people worldwide were living with HBV, and around 820,000 lives were lost because of it. Although we’ve made great strides in prevention and treatment, there’s still a lot to do to stop this global health threat.
Table of Contents
- What is Hepatitis B?
- Disease Spectrum and Progression of Chronic Hepatitis B
- Symptoms and Signs of Hepatitis B
- Prevention: How to Protect Against Hepatitis B
- Diagnosing and Treating Hepatitis B
- Complications of Chronic Hepatitis B
- Global Impact and Eradication Efforts
- Closing Thoughts
- References
What is Hepatitis B?
Structure and Genome of Hepatitis B Virus
HBV is quite small compared to many other viruses, measuring just 3.2 kb in genome size. Unlike typical DNA viruses, HBV does something unique when it replicates:
- It forms an RNA copy (an intermediate) before making new DNA.
- It can also slip its genetic material into the host’s DNA, which makes it stubborn and hard to clear from the body. This hidden presence often contributes to persistent infections [3, 2].
The Replication Cycle
This virus sets its sights on liver cells (also known as hepatocytes). Once inside, it changes its relaxed circular DNA (rcDNA) into a tougher version called covalently closed circular DNA (cccDNA). This cccDNA acts like a starting template, helping the virus churn out new viral RNA so it can multiply and spread. This complex process is a big reason why HBV can dig in for the long haul and avoid being completely eradicated from the body [4].
Disease Spectrum and Progression of Chronic Hepatitis B
Hepatitis B can show up in different forms, from mild to life-threatening conditions. Here are the main stages:
- Acute Hepatitis: This is a short-term infection that sometimes clears up on its own.
- Chronic Hepatitis: An infection that sticks around for a long time, placing continuous strain on the liver.
- Cirrhosis: When long-term inflammation scars the liver tissue so much that it struggles to function.
- Hepatocellular Carcinoma (HCC): A type of liver cancer often linked to ongoing HBV infection [2].
For those who develop chronic HBV, the chances of serious liver troubles, including end-stage disease and HCC, go way up. Chronic infection can lead to severe health issues such as liver failure, cirrhosis, and liver cancer, and may remain asymptomatic for years, complicating diagnosis and management [1].
Symptoms and Signs of Hepatitis B
Many individuals infected with the hepatitis B virus (HBV) do not exhibit symptoms, especially in the early stages. However, when symptoms do appear, they can vary depending on whether the infection is acute or chronic.
How is Hepatitis B Transmitted?
HBV is mainly spread through contact with infected blood or bodily fluids, making it what’s called a blood-borne pathogen [9]. The most common ways people catch HBV are:
- From an infected mother to her child during birth.
- Through unsafe injections or contaminated blood transfusions.
- By sharing needles or sharp tools, such as razors or syringes.
- Via unprotected sex with someone who already has HBV.
Prevention: How to Protect Against Hepatitis B
Hepatitis B Vaccine
The hepatitis B vaccine is the best way to keep this virus at bay. It’s both safe and highly effective, which is why global health campaigns push for widespread vaccination to cut down on new cases [5].
Hygiene and Safety Practices
Besides getting vaccinated, there are other steps that really help:
- Always use sterile or properly cleaned medical equipment.
- Take measures for safe sex to reduce exposure to bodily fluids.
- Thoroughly screen blood used for transfusions so it’s free of the virus.
Diagnosing and Treating Hepatitis B
Diagnosis
Catching HBV early can make a world of difference. Medical professionals typically use blood tests that check for signs of the virus in the body, such as HBV antigens or antibodies. They also regularly look at liver enzymes and other markers to see if the virus is causing ongoing damage [6, 8].
Treatment Options
Currently, there’s no perfect cure that wipes out HBV entirely. However, we do have treatments that hold the virus at very low levels, which slows down liver damage:
- Peginterferon alpha-2a: This is a type of immune-based therapy that helps the body fight the virus.
- Nucleos(t)ide Analogues: These are antiviral medicines that stop the virus from making copies of itself [7].
While these treatments control the infection, they usually don’t get rid of it completely [1]. Researchers are working on new antiviral and immunomodulatory therapies that might achieve what’s known as a functional cure, meaning people could keep the virus from causing harm even if it’s still hidden away [5].
Complications of Chronic Hepatitis B
Chronic hepatitis B can lead to several serious health complications, which underscore the importance of prevention and early treatment:
- Liver Damage: Ongoing infection with HBV can cause significant liver damage, leading to conditions such as cirrhosis and liver cancer.
- Cirrhosis: This is a severe condition where the liver becomes scarred and loses its ability to function properly. Cirrhosis can result from long-term inflammation caused by chronic hepatitis B.
- Liver Cancer: Chronic hepatitis B significantly increases the risk of developing liver cancer, a life-threatening condition that requires prompt medical attention.
- Liver Failure: In advanced cases, chronic hepatitis B can lead to liver failure, where the liver can no longer perform its vital functions.
Vaccination remains the most effective way to prevent hepatitis B infection. The hepatitis B vaccine is recommended for all adults, particularly those at higher risk, to protect against the severe health outcomes associated with chronic HBV infection.
Global Impact and Eradication Efforts
Chronic hepatitis B infection remains a major health crisis in many parts of the world, highlighting the importance of understanding chronic infections in the context of public health. Organizations like the World Health Organization (WHO) and other groups are aiming to:
- Expand Vaccination Programs: They want everyone, including newborns and high-risk groups, to receive the HBV vaccine.
- Raise Awareness: By teaching people how the virus spreads and what can stop it, fewer new infections occur.
- Push Research and Development: Advancing new treatments and investing in creative immunotherapies could one day put an end to HBV for good [10].
Even though big progress has been made, there’s still a long road ahead to cut down on infection rates and save lives from HBV-related complications.
Closing Thoughts
Hepatitis B is a layered viral infection that continues to challenge healthcare systems worldwide. Current treatments are good at slowing the virus and preventing severe liver disease, but not at wiping it out completely. There is hope on the horizon, though. As vaccination programs grow and new medicines come down the pipeline, global health experts see the possibility of eventually overcoming hepatitis B. By staying informed about how it spreads, what it does to the liver, and how to prevent it, communities around the world can help reduce its reach and improve everyone’s health.
References
[1] Peters M. G. (2019). Hepatitis B Virus Infection: What Is Current and New. Topics in antiviral medicine, 26(4), 112–116. https://pubmed.ncbi.nlm.nih.gov/30641484/
[2] Liang T. J. (2009). Hepatitis B: the virus and disease. Hepatology (Baltimore, Md.), 49(5 Suppl), S13–S21. https://doi.org/10.1002/hep.22881
[3] Li, H., Yan, L., Shi, Y., Lv, D., Shang, J., Bai, L., & Tang, H. (2020). Hepatitis B Virus Infection: Overview. Advances in experimental medicine and biology, 1179, 1–16. https://doi.org/10.1007/978-981-13-9151-4_1
[4] Tsukuda, S., & Watashi, K. (2020). Hepatitis B virus biology and life cycle. Antiviral research, 182, 104925. https://doi.org/10.1016/j.antiviral.2020.104925
[5] Jeng, W. J., Papatheodoridis, G. V., & Lok, A. S. F. (2023). Hepatitis B. Lancet (London, England), 401(10381), 1039–1052. https://doi.org/10.1016/S0140-6736(22)01468-4
[6] Yuen, M. F., Chen, D. S., Dusheiko, G. M., Janssen, H. L. A., Lau, D. T. Y., Locarnini, S. A., Peters, M. G., & Lai, C. L. (2018). Hepatitis B virus infection. Nature reviews. Disease primers, 4, 18035. https://doi.org/10.1038/nrdp.2018.35
[7] Yardeni, D., & Ghany, M. G. (2022). Review article: hepatitis B-current and emerging therapies. Alimentary pharmacology & therapeutics, 55(7), 805–819. https://doi.org/10.1111/apt.16828
[8] Guvenir, M., & Arikan, A. (2020). Hepatitis B Virus: From Diagnosis to Treatment. Polish journal of microbiology, 69(4), 391–399. https://doi.org/10.33073/pjm-2020-044
[9] Tsai, K. N., Kuo, C. F., & Ou, J. J. (2018). Mechanisms of Hepatitis B Virus Persistence. Trends in microbiology, 26(1), 33–42. https://doi.org/10.1016/j.tim.2017.07.006
[10] Komatsu H. (2014). Hepatitis B virus: where do we stand and what is the next step for eradication?. World journal of gastroenterology, 20(27), 8998–9016. https://pubmed.ncbi.nlm.nih.gov/25083074/
