ConditionInfections
Hepatitis B
Hepatitis B is a liver infection caused by the hepatitis B virus (HBV), spread through blood, sex and from mother to baby at birth. Most adults clear it within 6 months, but about 9 in 10 infected newborns develop lifelong (chronic) infection. Chronic hepatitis B often causes no symptoms for decades while it slowly damages the liver, leading to cirrhosis or liver cancer. There is no routine cure, but daily antiviral tablets control it, and a safe vaccine prevents it.
Also called: Hep B, HBV infection, hepatitis B virus infection, serum hepatitis
At a glance
- What it is
- A viral infection of the liver that can be short-lived (acute) or lifelong (chronic).
- How it spreads
- Blood, sex, shared needles or razors, and from mother to baby at birth. Not through food, kissing or hugging.
- Symptoms
- Often none. Acute illness can cause jaundice, fatigue, nausea and dark urine.
- Tests
- Blood tests for HBsAg, anti-HBs and anti-HBc, plus HBV DNA and liver tests if positive.
- Treatment
- Monitoring for all; tenofovir or entecavir tablets for those with active liver damage.
- Prevention
- A vaccine (2 or 3 doses) gives long-lasting protection.
When to get help
Call 911 or go to the ER
- Confusion, extreme drowsiness or unusual behavior with jaundice (possible liver failure)
- Vomiting blood or passing black, tarry stools in someone with liver disease
- Severe bleeding or bruising easily, with yellow skin or eyes
See a doctor within a day or two
- Yellow skin or eyes, dark urine and pale stools
- A rapidly swelling belly or legs in someone with chronic hepatitis B
- Possible exposure: a needlestick, sexual contact with an infected person or a shared needle (preventive treatment works best within 24 hours and up to 7 days)
- A baby born to a mother with hepatitis B who has not had the vaccine and immune globulin within 12 hours of birth
Book a routine appointment
- Never been tested for hepatitis B (CDC recommends a test for all adults at least once)
- Known chronic hepatitis B with no liver check in the last 6 to 12 months
- Planning pregnancy, chemotherapy, rituximab or other immune-suppressing treatment
What hepatitis B is
HBV infects liver cells. The virus itself does little direct harm. The damage comes from the immune system attacking infected cells, which causes inflammation (hepatitis). Over years, repeated inflammation leads to scarring (fibrosis), then cirrhosis, and raises the risk of liver cancer, even without cirrhosis.
More than 250 million people worldwide live with chronic hepatitis B, most in Asia and Africa, and many do not know they have it. In the US, people born in Asia, Africa and the Pacific Islands are most affected.
Acute vs chronic hepatitis B
| Acute | Chronic | |
|---|---|---|
| Definition | First 6 months after infection | Virus still present after 6 months |
| Chance of becoming chronic | About 90% if infected as a newborn, 25 to 50% at age 1 to 5, under 5% as an adult | Already established |
| Symptoms | None in most children; about a third to half of adults get ill | Usually none until liver damage is advanced |
| Main risk | Rare acute liver failure (under 1%) | Cirrhosis and liver cancer |
| Treatment | Supportive care | Antivirals for active disease, lifelong monitoring |
How hepatitis B is transmitted
The virus is present in blood, semen and vaginal fluids. It is far more infectious than HIV and can survive on surfaces for at least 7 days.
It spreads through:
- birth to a mother with hepatitis B (the commonest route worldwide)
- unprotected vaginal, anal or oral sex
- sharing needles, syringes or drug equipment
- sharing razors, toothbrushes or nail clippers
- needlestick injuries in health care
- unsterile tattooing, piercing or medical equipment
- close household contact with an infected person over years, through small cuts and sores
It does not spread through kissing, hugging, sharing food or cutlery, coughing, sneezing or breastfeeding.
Hepatitis B symptoms
Symptoms of acute infection start 1 to 6 months (on average about 3 months) after exposure and can last several weeks:
- tiredness and feeling unwell
- loss of appetite, nausea and vomiting
- pain or discomfort under the right ribs
- jaundice: yellow skin and whites of the eyes
- dark urine and pale, clay-colored stools
- joint pain, low fever and sometimes an itchy rash
Chronic hepatitis B is usually silent. When symptoms appear, they often signal advanced liver disease: swelling of the belly (ascites), easy bruising, confusion, vomiting blood or weight loss.
Hepatitis B tests and what results mean
CDC recommends that every adult is tested at least once, using a three-part panel:
| HBsAg | Anti-HBc (total) | Anti-HBs | What it usually means |
|---|---|---|---|
| Negative | Negative | Negative | Never infected, not immune: get vaccinated |
| Negative | Negative | Positive | Immune from vaccination |
| Negative | Positive | Positive | Past infection, recovered and immune |
| Positive | Positive | Negative | Current infection (acute or chronic) |
| Negative | Positive | Negative | Unclear: past infection, low-level infection or false positive; needs further testing |
IgM anti-HBc points to a recent (acute) infection. A positive HBsAg lasting more than 6 months confirms chronic infection.
If you have chronic hepatitis B, further tests show how active it is:
- HBV DNA (viral load): how much virus is in the blood
- HBeAg and anti-HBe: markers of how actively the virus is multiplying
- ALT: a liver enzyme that rises with inflammation
- Liver stiffness scan (FibroScan) or ultrasound: to measure scarring
- Tests for hepatitis D, hepatitis C and HIV, which share transmission routes
Hepatitis B treatment
Acute hepatitis B
Most adults recover without antiviral treatment. Care involves rest, fluids, adequate food and avoiding alcohol. Ask a doctor before taking acetaminophen (paracetamol) or any other medicine or supplement, since the liver processes them. Antivirals are used if the infection is severe or liver failure develops.
Chronic hepatitis B
Not everyone needs medicine immediately. Treatment is recommended when blood tests show active liver inflammation and significant viral levels, when there is cirrhosis, before chemotherapy or immune-suppressing drugs, and in some pregnancies.
- Tenofovir (TDF or TAF) or entecavir: one tablet a day. They suppress the virus in almost everyone who takes them, reduce liver scarring and lower the risk of liver cancer. Resistance is rare. Most people take them long term, and stopping without supervision can cause a dangerous flare.
- Pegylated interferon: weekly injections for 48 weeks, used for selected people. It has more side effects.
Current drugs rarely eliminate HBsAg (a "functional cure"), and new treatments aimed at cure are in clinical trials.
Living with chronic hepatitis B
- See a liver specialist or experienced primary care doctor every 6 to 12 months for blood tests, even if you feel well.
- Liver cancer surveillance: ultrasound, often with an AFP blood test, every 6 months for people with cirrhosis and other higher-risk groups.
- Avoid alcohol, or keep it to a minimum.
- Get vaccinated against hepatitis A.
- Check with your doctor before starting herbal remedies or new medicines.
- Make sure household members and sexual partners are tested and vaccinated.
- Cover cuts, do not share razors or toothbrushes, and use condoms with unvaccinated partners.
Hepatitis B in pregnancy
All pregnant people in the US are tested for HBsAg in each pregnancy. If the mother has hepatitis B:
- the baby receives the hepatitis B vaccine and hepatitis B immune globulin (HBIG) within 12 hours of birth, then completes the vaccine series, which prevents more than 9 in 10 infections
- mothers with a high viral load are usually offered tenofovir in the third trimester to lower the risk further
- breastfeeding is safe
- the baby is tested at 9 to 12 months to confirm protection
Hepatitis B vaccine
The vaccine is safe and protects more than 9 in 10 people who complete the series, likely for life.
- Babies: first dose within 24 hours of birth.
- Children and teens: catch-up if not vaccinated.
- Adults: recommended in the US for everyone aged 19 to 59, and for people 60 and older with risk factors or who want protection.
- Schedules: 2 doses one month apart (Heplisav-B) or 3 doses over 6 months, depending on the brand.
Health care workers have a follow-up antibody test to confirm immunity.
Complications
- Cirrhosis and liver failure
- Liver cancer (hepatocellular carcinoma)
- Hepatitis D (delta) co-infection, which causes faster liver damage
- Reactivation during chemotherapy or rituximab, which can be severe
- Kidney inflammation and blood vessel inflammation (rare)
Without treatment, about 1 in 4 people infected in childhood eventually die from cirrhosis or liver cancer. With monitoring and treatment, most people with chronic hepatitis B have a normal or near-normal life expectancy. For an overview of all types, see viral hepatitis.
Frequently asked questions
What are the first symptoms of hepatitis B?
Early symptoms include tiredness, loss of appetite, nausea, mild fever and aching joints, followed by dark urine, pale stools and yellowing of the skin and eyes. Many people, especially children, have no symptoms at all, so testing is the only way to know.
How is hepatitis B transmitted?
Through infected blood and body fluids: from mother to baby at birth, unprotected sex, sharing needles, razors or toothbrushes, and needlestick injuries. It does not spread through kissing, hugging, sharing food, coughing or breastfeeding.
Is hepatitis B curable?
Most adults with acute infection clear the virus on their own. Chronic hepatitis B cannot usually be cured, but daily antiviral tablets keep the virus suppressed, prevent liver damage from progressing and lower liver cancer risk. Research toward a cure is ongoing.
Can you live a normal life with hepatitis B?
Yes. Most people with chronic hepatitis B work, have relationships and have children normally. Regular liver checks, treatment when needed, avoiding alcohol and protecting partners through vaccination are the key steps.
What does a positive hepatitis B core antibody mean?
A positive anti-HBc means you have been infected with hepatitis B at some point. If HBsAg is negative and anti-HBs is positive, you recovered and are immune. If HBsAg is also positive, you have a current infection. Anti-HBc alone needs further testing.
Do I need a hepatitis B booster?
Most people who complete the vaccine series do not need a booster. Exceptions include people on dialysis, some people with weakened immunity, and health care workers whose antibody test after vaccination shows they did not respond.
Sources
This guide was written from current patient and clinical guidance, including:
- CDC: Clinical overview of hepatitis B
- CDC: Screening and testing recommendations for chronic hepatitis B virus infection (2023)
- World Health Organization: Hepatitis B fact sheet
- American Association for the Study of Liver Diseases (AASLD): Hepatitis B guidance
- MedlinePlus: Hepatitis B
- Advisory Committee on Immunization Practices (ACIP): Universal hepatitis B vaccination in adults