What Is Hepatitis B?

Hepatitis B is a viral infection that affects the liver and can be transmitted through sex. It’s caused by the hepatitis B virus (HBV) and spreads through contact with infected blood, semen, or vaginal fluids. Hepatitis B can cause short-term illness or develop into a long-term (chronic) infection that damages the liver over time.

Hepatitis B is the most common form of viral hepatitis that’s sexually transmitted. It’s also the only one that’s routinely screened for in STI testing and has a widely available vaccine.

How is it different from hepatitis A and C?

• Hepatitis A can be passed through oral-anal contact but is usually foodborne and causes short-term illness only.
• Hepatitis C is rarely transmitted through sex — it’s mostly spread through shared needles or blood exposure. Unlike B, there’s no vaccine, but it is curable.
• Hepatitis B is more infectious than HIV and the most likely to be spread through sex. Chronic HBV can lead to liver failure or cancer.

What Are Symptoms of Hepatitis B?

The tricky thing about hepatitis B is that it often doesn’t cause any symptoms at all — especially early on. When symptoms do appear, they usually show up between 1 to 4 months after exposure. Some people mistake them for the flu or a stomach bug and never think to get tested.

People with female biology may experience fatigue, nausea, abdominal bloating, or pain. Jaundice — a yellowing of the skin or eyes — is a classic sign, though not everyone gets it. You might also notice joint pain or a general sense of feeling unwell.

For people with male biology, symptoms are largely the same. Some report dark urine, pale stools, or a vague discomfort in the upper right side of the belly, where the liver is located. These symptoms can come on gradually or feel like a short-lived illness.

Anyone infected with hepatitis B can also have a low-grade fever, body aches, or loss of appetite. But again, many people never feel anything at all — which is why testing is so important.

How long can you have hepatitis B without knowing?

It’s possible to carry hepatitis B for years without symptoms. Some people discover it only after donating blood, starting a new job, or getting tested for another reason. That’s especially true for chronic infections, which can quietly damage the liver over time.

What Does Hepatitis B Look Like?

Hepatitis B doesn’t usually cause visible changes to the skin or genitals. When symptoms appear, they’re internal or generalized — like fatigue or jaundice.

Signs that might be noticed include:

• Yellowing of skin or eyes
• Dark-colored urine
• Clay-colored stool

Most people infected with HBV will not “look sick,” especially during the chronic phase.

How Is Hepatitis B Transmitted?

HBV spreads through direct contact with infected blood or bodily fluids, especially during sex. It can also be passed through sharing needles, from mother to child during birth, or through contaminated medical equipment.

Sexual transmission:

• Vaginal, anal, or oral sex without protection
• Sharing sex toys
• Microtears in mucous membranes allow viral entry

Can you get hepatitis B from kissing or casual contact?

No. HBV is not spread through saliva, hugging, coughing, or sharing food or drinks.

What about hepatitis A and C?

• Hepatitis A can be sexually transmitted via rimming or oral-anal contact, especially during outbreaks or in MSM communities. A vaccine is available.
• Hepatitis C is less often spread through sex but is possible in people with multiple partners, HIV, or rough sex that causes bleeding. It’s usually spread by needles, not fluids.

How Do You Test for Hepatitis B?

Testing for hepatitis B involves a simple blood test that looks for viral proteins and antibodies.

Common tests:

• HBsAg (Hepatitis B surface antigen): shows current infection
• Anti-HBs: shows immunity from past infection or vaccination
• Anti-HBc: shows past exposure to the virus

Who should get tested?

• People with new or multiple sexual partners
• MSM (men who have sex with men)
• People living with HIV
• Pregnant individuals
• Anyone with unexplained liver symptoms or a partner with HBV

Are hepatitis tests included in regular STI panels?

Not always. Make sure to ask for hepatitis B testing specifically. Testing for hepatitis A and C may also be available, especially if you’re at higher risk.

How Is Hepatitis B Treated?

If caught early, most healthy adults clear the infection on their own. Rest, hydration, and follow-up blood work are the main supports during acute infection.

Chronic hepatitis B treatment:

• Antiviral medications (e.g., tenofovir, entecavir)
• Regular liver monitoring
• Lifestyle changes to support liver health

There’s no cure for chronic hepatitis B yet, but treatment can suppress the virus and prevent liver damage.

Complications of Hepatitis B

Hepatitis B can lead to serious complications if left untreated:

• Chronic liver disease
• Cirrhosis (scarring of the liver)
• Liver cancer (hepatocellular carcinoma)
• Liver failure

Hepatitis C, if sexually acquired or via shared needles, can also become chronic and cause similar outcomes — but unlike HBV, it’s curable with medication.

Hepatitis A doesn’t lead to chronic disease, but it can cause severe illness in some adults.

Outlook & Prognosis

The outlook for hepatitis B depends on how early it’s detected and whether it becomes chronic. Most people who are infected as adults recover fully and develop lifelong immunity.

But those who develop chronic infection need ongoing care. With proper monitoring and treatment, people with chronic hepatitis B can live long, healthy lives.

Living With Hepatitis B

Being diagnosed with hepatitis B can feel overwhelming, but it doesn’t mean you’re untreatable or untouchable. It just means you need monitoring — and honesty with partners.

If you have chronic HBV:

• Follow up regularly with your doctor
• Avoid alcohol and liver toxins
• Use condoms to prevent transmission
• Tell future sexual partners or anyone sharing blood contact

It’s also a reminder to take care of your body, get vaccinated for hepatitis A, and stay informed.

How to Tell Your Partner(s) You Have Hepatitis B

This conversation might feel tough — but it’s part of building trust and protecting their health. You can say:

“I’ve tested positive for hepatitis B. It’s a liver infection that can be passed through sex. I’m being monitored and/or treated, and I wanted to share that with you so we can talk about testing or vaccination.”

Things to include:

• It’s manageable — and often clears on its own
• There’s a vaccine that protects partners
• You’re sharing this because you care and want to be honest

Most people appreciate being informed, especially when you lead the conversation calmly and clearly.

Last reviewed: May 2025
This content is regularly reviewed and updated to reflect the latest medical guidelines.

Quick Facts About Hepatitis B

• Caused by: Virus (Hepatitis B virus — HBV)
• Spread through: Sex, blood, semen, vaginal fluids, birth
• Symptoms: Often none; may include fatigue, jaundice, dark urine, abdominal pain
• Testing: Blood test for hepatitis B surface antigen (HBsAg)
• Treatment: Acute cases resolve on their own; chronic cases may require antiviral meds
• Risk if untreated: Chronic liver disease, cirrhosis, liver cancer
• How common: About 880,000 people in the U.S. have chronic HBV (CDC)