Hepatitis B: What It Is, Causes, Symptoms & Treatment

Introduction

Have you ever felt very tired for many days or noticed your eyes looking a little yellow? These can be Hepatitis B symptoms¹. Hepatitis B is a liver infection caused by the Hepatitis B virus (HBV). This virus can make the liver swollen and affect how it works².

One tricky thing about Hepatitis B is that many people do not feel sick at all in the beginning. Some people may not have any symptoms for a long time, even for many years. But when symptoms do appear, they can include feeling tired, fever, stomach pain, loss of appetite, dark urine, or yellow skin and eyes¹.

In India, about 29.8 million people were living with Hepatitis B in 2022, showing a significant health burden in the country³.

If Hepatitis B becomes long-term, it can lead to serious liver problems like chronic liver disease (long-lasting liver damage), cirrhosis (serious scarring of the liver), liver failure and hepatocellular carcinoma (a type of liver cancer)⁴. That is why it is important to learn about it early.  

In this blog, you will understand what is Hepatitis B, how it spreads, its symptoms, treatment, and ways to prevent it. 

What is Hepatitis B?

Hepatitis B is a viral infection mainly affecting the liver. It is caused by the Hepatitis B virus and spread through infected blood and body fluids like semen and vaginal secretions. After entering the body, the virus reaches the liver and infects its cells. The infection does not cause symptoms immediately. It may take 30–180 days for signs to appear, and many people may not notice any signs or symptoms in the early stage. 

During infection, the body’s immune system tries to remove the infected liver cells by attacking them. Special immune cells called cytotoxic T lymphocyte cells help in destroying these infected liver cells. This can also lead to inflammation and damage in the liver. In some cases, the virus may continue to stay in the body and slowly affect liver health over time⁴.

Types of Hepatitis B

Hepatitis B infection can be of two main types: acute and chronic. These types of Hepatitis B infection are based on how long the virus stays in the body and how it affects the liver⁵.

1. Acute Hepatitis B

This is a short-term infection where the virus stays in the body for a limited time and then clears. It can last for a few weeks and sometimes up to 6 months. Doctors often identify this stage when a marker for hepatitis B called HBsAg, is present in the body for less than 6 months⁴. Most healthy adults and children above 5 years get rid of infection naturally and recover completely⁵. During this stage, the liver may show changes like damage to liver cells and inflammation due to infection⁴.

2. Chronic Hepatitis B

This is a long-term infection where the virus stays in the body for a longer time. This type is usually identified when the HBsAg marker stays in the body for longer than 6 months. The chance of this happening is higher in infants and young children. About 90% of infants, 25–50% of young children, and 5% of adults may develop this type⁵. If the inflammation continues for many years, it can lead to liver scarring (fibrosis), severe liver scarring (cirrhosis), and liver cancer (hepatocellular carcinoma)⁴. 

Causes of Hepatitis B

Hepatitis B spreads mainly through direct exposure to infected blood and body fluids in different every day or medical situations⁶. The most common Hepatitis B causes include: 

• Unprotected sexual contact, including vaginal, oral, or anal sex with an infected person 
• Contact with infected body fluids such as blood, semen or vaginal secretions⁴
• Sharing needles, syringes, or sharp objects used for drugs, tattooing, or piercing 
• Needle stick injuries or accidental exposure to infected blood⁶ 
• In rare cases, unsafe medical procedures like injections, surgery, or blood transfusion when proper safety is not followed².
• Mother-to-child spread during birth (perinatal transmission)⁴
• Close contact between children involving exposure to infected body fluids 
• Sharing or reusing contaminated sharp tools in healthcare or community settings⁶ 

Note that the virus spreads through direct contact with infected fluids, not through casual contact like touching,talking⁴, hugging, kissing, coughing, sneezing, breastfeeding (if nipples are not cracked or bleeding and the infant is vaccinated), or sharing food and drinks⁷.

Symptoms of Hepatitis B

Many people may not have any Hepatitis B symptoms, especially in the early stage of infection¹. When symptoms do appear, they usually develop after an incubation period of 30–180 days following exposure to the virus⁵. Common symptoms of Hepatitis B include: 

• Feeling very tired or weak (fatigue)⁴
• Fever or increased body temperature¹
• Pain or swelling in joints (arthralgia or arthritis) 
• Pain or discomfort in the abdomen (stomach area)⁴
• Loss of appetite or not feeling like eating 
• Nausea and vomiting (feeling like throwing up) 
• Dark-coloured urine or pale stools 
• Yellowing of the skin or eyes (jaundice)¹
• Skin rash in some cases, as part of a serum sickness–like syndrome, a temporary immune reaction that can cause rash, joint pain, and fever during acute Hepatitis B infection⁴.

Because Hepatitis B symptoms may be mild or absent, early detection is important, and the diagnosis is confirmed using blood tests such as HBsAg and other hepatitis B serologic markers^4,5.

Risk Factors

Risk factors are situations or behaviours that increase the chance of coming into contact with the virus. These do not cause the infection directly but make exposure more likely⁵. 

Factors that increase the risk include: 

• Having unprotected sex or multiple sexual partners 
• Sharing needles or injecting drugs 
• Being born to a mother who has Hepatitis B 
• Living with someone who has Hepatitis B and being exposed to their blood or body fluids⁵
• Being unvaccinated, especially in higher-risk settings⁶
• Being born or living in areas where Hepatitis B is more common 
• Having infections like HIV or hepatitis C 
• Working in jobs with exposure to blood, needles, or body fluids 
• Being on kidney dialysis 
• Living or working in crowded places like prisons where exposure risk is higher⁵

These factors increase risk because they raise the chances of contact with infected blood or body fluids⁵. Reducing exposure and following safety measures can help lower this risk⁶.

Complications

Hepatitis B may lead to serious complications. These complications can affect how the liver works and may become severe over time. Some important complications include: 

• Acute liver failure: It is a rare but severe complication of acute Hepatitis B infection, where the liver rapidly loses function and may show problems like bleeding tendency and brain dysfunction (encephalopathy); in severe cases, liver transplantation may be required^5,8.
• Cirrhosis: Long-term infection with   healthy liver cells to develop scar tissue, affecting normal liver function. Decompensated cirrhosis or end-stage liver disease may occur, leading to complications such as fluid accumulation in the abdomen (ascites), vomiting of blood due to swollen veins (variceal bleeding), confusion due to toxin buildup (encephalopathy), and jaundice⁹. 
• Liver failure: Severe damage leads to end-stage liver disease where the liver cannot function properly.
• Liver cancer: Chronic infection increases risk to cancer of liver cells, so regular tests and scans help in early detection^4,5.
• Reactivation: The virus may become active again later in life and damage the liver after being quiet. HBV reactivation commonly occurs during conditions of weakened immunity such as chemotherapy, steroid therapy, biologic drugs, or after organ transplantation¹⁰.
• Hepatitis D: People with hepatitis B can also get hepatitis D, which worsens liver damage⁵.

These complications can become life-threatening as the disease progresses. Patients with hepatitis B should be monitored closely for these risks. 

Diagnosis of Hepatitis B

Hepatitis B is diagnosed using a combination of medical history, physical examination, blood tests, and sometimes imaging tests as explained below:⁴

• Medical and family history: Doctors ask about symptoms like fatigue, abdominal pain, nausea, vomiting, dark urine, and jaundice. They also check important risk factors such as unprotected sexual contact, intravenous drug use, healthcare exposure, and close contact with infected persons. Family history of hepatitis B or liver cancer is also important for risk assessment^4,5.
• Physical examination: Doctors look for signs of liver damage such as yellowing of the eyes or skin (jaundice), swelling in the abdomen, and swelling in the legs or feet. In long-term disease, signs like enlarged liver or spleen and fluid in the abdomen may be seen^4,5.
• Blood tests: Blood tests are the most important method used to confirm hepatitis B and understand the stage of infection.  
  • HBsAg(hepatitis B surface antigen), a viral protein found on the surface of the hepatitis B virus, shows a current active infection.  
  • Anti-HBs (antibody to hepatitis B surface antigen), a protective antibody, indicates immunity due to vaccination or past recovery.  
  • Anti-HBc IgM (IgM antibody to hepatitis B core antigen), an early immune response antibody, suggests a recent or acute infection. 
  • Anti-HBc IgG (IgG antibody to hepatitis B core antigen), a long-lasting antibody, indicates past or long-term infection.  
  • HBeAg (hepatitis B e antigen), a marker of active viral replication, indicates how active the virus is. 
  • HBV DNA (measurement of viral genetic material in blood) shows viral load that is the amount of virus in the body. It indicates how active the virus is and how quickly it is multiplying in the body¹¹.   

Blood tests are used to detect hepatitis B markers such as HBsAg and other antibodies. Together, these tests help doctors understand whether the infection is new (acute) or long-term (chronic), how active the virus is, and whether Hepatitis B treatment is needed^4,5 Blood tests can also show if a person is immune due to vaccination or past infection⁵.  

• Liver function tests: Tests like ALT and AST are done to check for liver inflammation and injury⁴. 
• Imaging and special tests: Imaging tests help check liver damage and complications. Ultrasound is a scan that shows the structure of the liver and is mainly used to screen for liver cancer (HCC) in long-term hepatitis B.  

Elastography measures liver stiffness to detect scarring (fibrosis)¹¹. 

In some cases, a liver biopsy may be done if more detailed information is needed⁵.

These tests together help confirm Hepatitis B and understand whether the infection is acute or chronic and how much the liver is affected^4,5.

For broader screening of related infections and sexually transmitted conditions, comprehensive profiles such as an STD panel may also be used, which can include Hepatitis B testing as part of a wider evaluation. You can learn more about this combined testing package here. 

Treatment Options

Treatment of hepatitis B depends on whether the infection is acute (short-term) or chronic (long-term) and how severe the liver damage is. Doctors choose treatment after checking symptoms, blood tests, and liver condition^4,12 Here are some Hepatitis B treatment options, based on the type and severity of infection: 

• Rest and supportive care: Most adults with a healthy immunity having acute hepatitis B  recover spontaneously and do not need antiviral drugs because the infection often clears naturally. Treatment is mainly supportive⁴. Patients are advised to take adequate rest, maintain proper hydration, follow a balanced and nutritious diet, and avoid alcohol and other hepatotoxic (liver-harming) substances. Mild cases can be managed at home, while severe cases may need hospital care for monitoring¹².
• Antiviral medicines in severe acute cases: In rare severe infections, antiviral medicines are used. This is required when there are signs of serious liver damage such as high bilirubin, raised INR, or liver failure. Drugs like tenofovir or entecavir may be given to control the virus and protect the liver⁴. 
• Chronic hepatitis B treatment: Not all chronic cases need treatment. Doctors assess liver enzymes, viral load, and liver condition before starting therapy. If needed, long-term antiviral medicines such as tenofovir, entecavir, lamivudine, or interferons are used⁴ These help reduce virus activity and prevent complications like cirrhosis and liver cancer, but they may not fully cure the infection.

Prevention

Hepatitis B prevention mainly focuses on vaccination and reducing contact with infected blood and body fluids^5,13. Here are some ways to prevent hepatitis B infection: 

• Getting the hepatitis B vaccine is the best protection, and it is recommended for most people^5,13. The vaccine is given in a 2-, 3-, or 4-dose schedule depending on age and vaccine formulation, which helps the body build long-term protection against the virus¹⁴.
• Pregnant women should get tested during pregnancy so infection can be found early. In newborn babies born to infected mothers, hepatitis B vaccine along with hepatitis B immunoglobulin (HBIG) should ideally be given within 12 hours of birth as early administration greatly reduces the risk of transmission from mother to child^13,15.
• Using condoms during sex helps reduce the spread of hepatitis B because the virus can be present in sexual body fluids⁵.
• Do not share needles or injection equipment, and make sure tattoo or piercing tools are properly sterilized. Avoid sharing personal items like toothbrushes or razors⁵.
• If someone is exposed to the virus, post-exposure prophylaxis (hepatitis B vaccine with or without Hepatitis B immunoglobulin [HBIG], a protective antibody injection) should be started as soon as possible ideally within 24 hours to prevent infection, because its protective effect decreases when there is delay⁵.  After sexual exposure, HBIG is generally not given beyond 14 days after exposure¹⁶.
• People traveling to areas with high hepatitis B cases should make sure their vaccination is up to date before travel^5,13.

Hepatitis B prevention is important because it can cause serious long-term liver problems, but vaccination and safe practices can greatly reduce the risk of infection and protect both individuals and families effectively. 

When to See a Doctor?

You should see a doctor in the following situations if you suspect hepatitis B or are at risk of infection⁵: 

• If you may have been exposed to infected blood or body fluids  
• If you develop Hepatitis B symptoms like tiredness, fever, nausea, vomiting, abdominal pain, dark urine, light-coloured stool, or jaundice
• If you are pregnant, as routine screening is recommended during pregnancy  
• If you belong to a high-risk group or have had close contact with someone infected  

Seeing a doctor early helps with proper testing, diagnosis, and monitoring of liver health, and it can reduce the risk of serious complications⁵.

Also Read: Liver Fibrosis: What Is It, Causes, Symptoms & Treatment

Conclusion

Hepatitis B is a serious liver infection, but it can be prevented in many cases. Getting vaccinated is the most important step because it protects the body from the virus. Early testing also helps find the infection before it damages the liver. Many people may not feel sick in the beginning, so regular check-ups are important. A healthy lifestyle like eating well, avoiding alcohol, and following safe practices can also protect the liver. With awareness, early detection and appropriate medical care, the risk of severe outcomes from hepatitis B can be greatly reduced.

Frequently Asked Questions (FAQs)

References

1. Hepatitis B Basics | Hepatitis B | CDC. Accessed May 5, 2026. https://www.cdc.gov/hepatitis-b/about/index.html 

2. Hepatitis B Basic Information | HHS.gov. Accessed May 5, 2026. https://www.hhs.gov/hepatitis/learn-about-viral-hepatitis/hepatitis-b-basics/index.html 

3. Swaroop S, Shalimar, Acharya SK. Hepatitis B virus prevalence in India: A wake-up call for action. Indian J Gastroenterol. 2025;44(5):585-587. doi:10.1007/s12664-025-01804-5  https://link.springer.com/article/10.1007/s12664-025-01804-5

4. Tripathi N, Mousa OY. Hepatitis B. In: StatPearls [Internet]. StatPearls Publishing; 2023. Accessed May 5, 2026. https://www.ncbi.nlm.nih.gov/books/NBK555945/ 

5. Hepatitis B – NIDDK. Accessed May 5, 2026. https://www.niddk.nih.gov/health-information/liver-disease/viral-hepatitis/hepatitis-b 

6. World Health Organisation. Hepatitis B. Accessed May 5, 2026. https://www.who.int/news-room/fact-sheets/detail/hepatitis-b 

7. Guvenir M, Arikan A. Hepatitis B Virus: From Diagnosis to Treatment. Pol J Microbiol. 2020;69(4):391-399. doi:10.33073/pjm-2020-044  https://pubmed.ncbi.nlm.nih.gov/33574867/

8. Bernal W, Wendon J. Acute Liver Failure. N Engl J Med. 2013;369(26):2525-2534. doi:10.1056/NEJMra1208937  https://pubmed.ncbi.nlm.nih.gov/24369077/

9. Gustot T, Stadlbauer V, Laleman W, Alessandria C, Thursz M. Transition to decompensation and acute-on-chronic liver failure: Role of predisposing factors and precipitating events. J Hepatol. 2021;75:S36-S48. doi:10.1016/j.jhep.2020.12.005 https://pubmed.ncbi.nlm.nih.gov/34039491/

10. Papatheodoridis GV, Lekakis V, Voulgaris T, et al. Hepatitis B virus reactivation associated with new classes of immunosuppressants and immunomodulators: A systematic review, meta-analysis, and expert opinion. J Hepatol. 2022;77(6):1670-1689. doi:10.1016/j.jhep.2022.07.003  https://pubmed.ncbi.nlm.nih.gov/35850281/

11. Cornberg M, Sandmann L, Jaroszewicz J, et al. EASL Clinical Practice Guidelines on the management of hepatitis B virus infection. J Hepatol. 2025;83(2):502-583. doi:10.1016/j.jhep.2025.03.018  https://www.journal-of-hepatology.eu/article/S0168-8278(25)00174-6/fulltext

12. CDC. Treatment of Hepatitis B. Hepatitis B. February 14, 2025. Accessed May 5, 2026. https://www.cdc.gov/hepatitis-b/treatment/index.html 

13. CDC. Hepatitis B Prevention and Control. Hepatitis B. September 24, 2025. Accessed May 5, 2026. https://www.cdc.gov/hepatitis-b/prevention/index.html 

14. Viral Hepatitis – STI Treatment Guidelines. February 27, 2023. Accessed May 8, 2026. https://www.cdc.gov/std/treatment-guidelines/hbv.htm 

15. A Comprehensive Immunization Strategy to Eliminate Transmission of Hepatitis B Virus Infection in the United States </P><P>Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of Infants, Children, and Adolescents. Accessed May 8, 2026. https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm 

16. Appendix C: Postexposure Prophylaxis of Persons with Discrete Identifiable Exposures to Hepatitis B Virus (HBV). Accessed May 8, 2026.  https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a4.htm  

17. Patel A, Dossaji Z, Gupta K, et al. The Epidemiology, Transmission, Genotypes, Replication, Serologic and Nucleic Acid Testing, Immunotolerance, and Reactivation of Hepatitis B Virus. Gastro Hep Adv. 2024;3(2):139-150. doi:10.1016/j.gastha.2023.10.008 https://pubmed.ncbi.nlm.nih.gov/39129942/

18. CDC. HIV and Viral Hepatitis. June 2016. Accessed May 5, 2026. https://stacks.cdc.gov/view/cdc/48584

19. Hepatitis B and Liver Cancer HBF Fact Sheet. Accessed May 5, 2026. https://www.hepb.org/assets/Uploads/Hepatitis-B-and-Liver-Cancer-HBF-Fact-Sheet2.pdf 

20. Tran TT. Hepatitis B virus in pregnancy. Clin Liver Dis. 2013;2(1):29-33. doi:10.1002/cld.159 https://pmc.ncbi.nlm.nih.gov/articles/PMC6448610/

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