The term "autoimmune hepatitis" describes liver inflammation driven by your own immune system, but the question most people are really asking is about hepatitis B — a vaccine-preventable, blood-borne and sexually transmitted liver infection. HBV is caused by a virus, and you can prevent it with a shot.
treatable, not curable
testing, not symptoms, decides
| Item | Value |
|---|---|
| Curable? | managed — treatable, not curable |
| Tested by | exam + lab |
| Often | no symptoms |
| If you may have it | get tested — testing, not symptoms, decides |
A quick word on the difference, because the wording trips people up. Autoimmune hepatitis means the immune system mistakenly attacks healthy liver cells and isn't passed between people. Viral hepatitis B is caused by the hepatitis B virus (HBV) and spreads through blood and body fluids. This article focuses on hepatitis B — what it is, how it behaves, and what to do about it. It's testable, treatable, and largely preventable through screening and a vaccine.
What hepatitis B actually is
Hepatitis B is a liver infection caused by HBV, a virus carried mainly in blood, semen, and other body fluids CDC. Clinicians split it into two stages. Acute hepatitis B is the short-term illness in the first six months after exposure, and many adults clear it on their own. Chronic hepatitis B lasts beyond six months and can be lifelong. The virus settles into liver cells, and over years the ongoing inflammation causes harm.
Age at the time of infection decides almost everything. Caught as an adult, HBV becomes chronic in only a small fraction of people; about ninety-five percent of adults clear it. Caught in infancy, it becomes lifelong in roughly nine out of ten babies WHO. That's why prevention is built around the newborn period and the birth-dose vaccine.
Symptoms — and the silent reality
Most people with hepatitis B feel nothing. Acute illness, when it does show up, can bring fatigue, fever, poor appetite, nausea, abdominal pain, dark urine, clay-colored stools, joint pain, and jaundice, a yellowing of the skin and the whites of the eyes that happens when the inflamed liver can't clear bilirubin. But most people with chronic HBV have no symptoms at all, sometimes for decades, while quiet liver damage accumulates.
That gap between how you feel and what's happening inside is the reason for screening. You can read a fuller breakdown of warning signs on our hepatitis b symptoms page. Feeling fine doesn't rule it out.
How hepatitis B spreads
HBV spreads when blood, semen, or other body fluids from an infected person enter someone who isn't infected. The common routes are sex, sharing needles or other injection equipment, and from a pregnant parent to the baby around the time of birth, which is the most common way young children become infected.
It does not spread through sneezing, coughing, hugging, sharing utensils, or food and water. After exposure, symptoms, if they appear, show up on average about ninety days later, with a range of roughly two to five months CDC surveillance. That window is long and often silent, so testing on a schedule catches infections that waiting for symptoms misses; here's when to test after exposure.
How hepatitis B is tested
Diagnosis comes from a blood draw run as a triple serologic panel CDC testing. Each marker answers a different question:
- HBsAg (hepatitis B surface antigen) — a positive result means active infection, acute or chronic.
- Anti-HBs (surface antibody) — signals immunity, either from recovering or from the vaccine.
- Total anti-HBc (core antibody) — marks past or current infection; it doesn't come from the vaccine.
The CDC now recommends that all adults aged eighteen and older be screened at least once in their lifetime, and that pregnant people be screened in each pregnancy CDC, 2023. Testing is a routine blood sample, results usually back in a few days, and free or low-cost at health departments, Planned Parenthood, and Title X clinics. If you'd rather sort out where to go, you can get tested or compare testing providers.
Treatment: what's realistic
Acute hepatitis B usually needs only supportive care — rest, fluids, and monitoring — while your body clears the virus CDC STI guidelines. Most acute cases don't need a rushed antiviral.
Chronic hepatitis B is a different conversation. There's no cure, but FDA-approved antivirals — tenofovir or entecavir — suppress the virus, calm liver inflammation, and lower the long-term risk of liver cancer AASLD, 2018. The goal is control: most people who start treatment stay on it for life, and viral clearance happens in only a small percentage even after a decade of therapy. This care belongs with a liver specialist who tracks your viral level and liver health over time. If you're prescribed medication, take it exactly as directed and don't stop because you feel well, since stopping abruptly can let the virus rebound.
Complications if it's left untreated
Untreated chronic hepatitis B causes harm slowly and silently. Over years the persistent inflammation can lead to:
- Cirrhosis — scarring that gradually replaces working liver tissue, eventually impairing the organ's ability to filter blood and make proteins.
- Liver cancer (hepatocellular carcinoma) — HBV is one of the leading causes worldwide, and the risk exists even without cirrhosis.
- Liver failure and death — the end stage when too much of the liver is destroyed.
Antiviral treatment is designed to interrupt this trajectory, so finding chronic infection early through screening changes outcomes.
Prevention
Vaccination is the single best protection. ACIP recommends the hepatitis B vaccine for all adults aged nineteen through fifty-nine, and for adults sixty and older who have risk factors CDC, 2022. The vaccine is safe, well-established, and gives durable immunity — more detail lives on our hepatitis vaccines page.
If you've been exposed to a known HBsAg-positive source and aren't already immune, post-exposure prophylaxis is hepatitis B immune globulin (HBIG) plus the vaccine, given as soon as possible, ideally within a day of exposure. Beyond that, condoms used every time lower risk for sexual transmission, never sharing needles or injection equipment closes off another route, and routine testing catches the infections that show no symptoms.
Newborn prevention deserves its own mention because it works so well. Every pregnancy is screened for HBsAg, and every newborn gets the hepatitis B vaccine at birth; a baby born to an HBsAg-positive parent also receives HBIG, both within hours of delivery CDC perinatal. Pairing the vaccine with HBIG, and adding an antiviral for parents with a high viral load, prevents most transmission. We cover this fully on our hepatitis and pregnancy page.
When to see a clinician
Talk to a clinician if you've never been screened, if you might have been exposed through sex or shared needles, if you're pregnant, or if you have symptoms like jaundice, dark urine, or unexplained fatigue. Clinics handle this diagnosis every day. Ask whether recent partners should be tested or vaccinated so the infection doesn't keep circulating.
Below is a quick reference for how the two stages of hepatitis B differ in practice:
| Acute hepatitis B | Chronic hepatitis B | |
|---|---|---|
| Duration | Within the first 6 months after exposure | Lasts beyond 6 months, often lifelong |
| Symptoms | May cause fatigue, jaundice, nausea — or none | Usually no symptoms for years |
| Typical treatment | Supportive care while the body clears it | Lifelong antivirals (tenofovir/entecavir) to suppress the virus |
| Who manages it | Primary care, monitoring | Liver specialist |
| Main risk | Most adults recover fully | Cirrhosis, liver cancer if untreated |