What Is Hepatitis D? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Hepatitis D (also called “hepatitis delta” or HDV) is the viral version of a party crasher with a very specific rule:
it can’t show up unless hepatitis B (HBV) is already there. In other words, HDV is a “plus-one” virusit needs
hepatitis B to infect you and to keep going in your body. That unique relationship is the whole story… and also why
hepatitis D can be more serious than hepatitis B alone.

This guide breaks down what hepatitis D is, how it spreads, what symptoms can look like, how doctors diagnose it,
what treatments exist in the U.S., and how to prevent it. (Spoiler: preventing hepatitis B is the single best way to
prevent hepatitis D.)

Quick note: This article is for general education, not personal medical advice. If you think you’ve been exposed to hepatitis B or D, or you already have hepatitis B, talk with a healthcare professional for testing and next steps.

Hepatitis D in Plain English: The “Plus-One” Virus

Hepatitis D is a liver infection caused by the hepatitis D virus (HDV). HDV is unusual because it can only infect
people who also have hepatitis B. If hepatitis B is the “key,” HDV is the “keychain charm” that can’t exist without it.
(Yes, that analogy is mildly ridiculous. No, your liver does not find it funny.)

When someone has both HBV and HDV, liver inflammation and damage can progress faster, and the risk of complications
like cirrhosis and liver cancer can be higher. That’s why many liver specialists take hepatitis D seriouslyeven if you
don’t hear about it as often as hepatitis A, B, or C.

Coinfection vs. Superinfection (Why Timing Matters)

Doctors talk about hepatitis D in two main scenarios:

• Coinfection: You get hepatitis B and hepatitis D at the same time.
• Superinfection: You already have chronic hepatitis B, and later you get hepatitis D.

The difference isn’t just vocabularyit affects what can happen next. With coinfection, many adults clear the viruses
and do not develop chronic infection. With superinfection, the odds of developing chronic hepatitis B and chronic
hepatitis D are much higher. Practically, superinfection is one reason a person with stable chronic hepatitis B can suddenly
worsen and develop more aggressive liver disease.

Example: Imagine two people:
(1) Sam is exposed to HBV and HDV at the same time and gets sick for a few weeksthen improves.
(2) Taylor has lived with chronic hepatitis B for years with few symptoms, then later gets HDV and suddenly develops
more intense symptoms and rising liver enzymes. That second scenario can be a red flag for HDV superinfection.

How Hepatitis D Spreads

Hepatitis D spreads the same way hepatitis B spreads: mainly through contact with infected blood and certain body fluids.
It is not spread through casual contact like hugging, sharing utensils, or sitting next to someone on the couch
(so you can keep your friendships and your snacks).

Common routes of transmission

• Sharing needles or injection equipment
• Unprotected sex with an infected partner
• Needlestick injuries (occupational exposure)
• Household exposure to blood (for example, sharing razors or nail clippers)

What does not spread hepatitis D

• Being coughed or sneezed on
• Sharing food, drinks, forks, or spoons
• Hugging, shaking hands, or sitting near someone
• Food or water contamination

Mother-to-baby transmission during birth appears to be uncommon. Breastfeeding is generally considered safe when proper
steps are taken to prevent hepatitis B transmission to the newborn, though bleeding or cracked nipples may change the
risk discussionsomething to review with a clinician.

Symptoms: What You Might Notice (and What Your Liver Might Notice First)

Hepatitis D symptoms can look like symptoms of other viral hepatitis infections. Some people have clear symptoms. Others
may have few symptoms until liver damage becomes more advanced. Symptoms often show up a few weeks after infection,
but the timeline and intensity can varyespecially between coinfection and superinfection.

Possible symptoms of acute hepatitis D

• Fatigue (the “why am I tired after doing nothing?” kind)
• Fever
• Loss of appetite, nausea, vomiting, or stomach pain
• Joint pain
• Dark urine and pale/clay-colored stools
• Jaundice (yellow skin or eyes)

Chronic infection can be quietuntil it isn’t

Many people with chronic hepatitis D have few symptoms for a long time. When symptoms do show up, they may reflect
complications such as cirrhosis. Those can include persistent fatigue, itchy skin, swelling in the legs (edema),
belly swelling from fluid (ascites), unexpected weight loss, and confusion or trouble concentrating.

When to seek urgent help

If someone has severe jaundice, confusion, significant bruising or bleeding, intense abdominal swelling, or signs of
acute liver failure, that’s an emergency. Call local emergency services or go to an ER immediately.

Causes and Risk Factors

The cause of hepatitis D is simple: infection with the hepatitis D virus. The “complicated” part is that HDV needs
hepatitis B to infect humans and to replicate. That’s why you’ll often see hepatitis D discussed as a “satellite” or
“defective” virusit can’t fully function on its own.

Who is at higher risk?

Because HDV requires HBV, the biggest risk factor is already having hepatitis B. Beyond that, risk factors overlap
with hepatitis B transmission patterns. People who may be at increased risk include:

• People with hepatitis B (especially if not previously tested for HDV)
• People who inject drugs or share injection equipment
• Sex partners or household contacts of someone with HBV/HDV
• Men who have sex with men
• People living with HIV and hepatitis B
• Hemodialysis patients and certain occupational exposure groups
• People who have lived in or emigrated from regions where hepatitis D is more common

Diagnosis: The Two-Test Reality Check

Since hepatitis D can only occur with hepatitis B, diagnosis often starts with hepatitis B testing (for example, a
positive hepatitis B surface antigen test). If hepatitis B is present, clinicians may look for hepatitis Despecially
if there are risk factors or unexplained liver inflammation.

Step 1: Anti-HDV total antibody test

This blood test looks for antibodies to hepatitis D, which can indicate current or past exposure.

Step 2: HDV RNA test

If the antibody test is positive, the next step is typically an HDV RNA test (qualitative or quantitative) to confirm
whether the virus is currently active in the blood.

Other tests doctors may use

Diagnosis and monitoring often involve more than “Do you have it: yes/no.” Doctors may also order tests to understand
liver health and complications:

• Liver function tests (like ALT/AST) to assess inflammation
• Tests to evaluate liver scarring (such as elastography)
• Imaging (ultrasound or other scans) to check for cirrhosis or tumors
• Liver biopsy in select cases if other tests don’t provide enough clarity

Why hepatitis D can be missed

Hepatitis D is not always routinely screened in every setting, and testing practices can vary. Some guidance has focused
on testing higher-risk groups, while patient advocacy groups have pushed for broader testing among people living with hepatitis B.
The practical takeaway is straightforward: if you have hepatitis B, ask your clinician whether you should be tested for hepatitis D.

Treatment: What Doctors Can Do Today (and What’s Coming Next)

Here’s the honest (and admittedly frustrating) headline: in the United States, no medicines are approved specifically
to treat hepatitis D. That does not mean “nothing can be done.” It means treatment is a mix of careful monitoring,
hepatitis B management, selected antiviral/immune-based therapies used in certain cases, and aggressively preventing and treating complications.

Supportive care and specialist management

For acute hepatitis, care may focus on managing symptoms, monitoring liver function, and avoiding anything that can
further injure the liver. Severe cases may require hospitalization.

Interferon-based therapy (sometimes used, not for everyone)

In some cases, doctors may recommend interferon-based therapy (for example, forms of interferon used for other viral
hepatitis conditions). Interferon treatment can be lengthy (often around a year in some references) and can cause side
effectsso it’s typically managed by a liver specialist who can weigh risks, benefits, and eligibility.

Because response to interferon can vary, follow-up testing (including HDV RNA levels and liver enzymes) helps determine
whether treatment is working and whether the plan should be adjusted.

Treating hepatitis B alongside hepatitis D

Everyone with hepatitis D also has hepatitis B, and many patients will need hepatitis B management as part of their care.
Even though hepatitis B treatments may not directly eliminate hepatitis D, controlling hepatitis B and monitoring liver health
remain critical pieces of the overall strategy.

Complication management: cirrhosis, liver cancer screening, and transplant

If chronic hepatitis D leads to cirrhosis, care often expands to include managing fluid retention, preventing bleeding
complications, evaluating mental status changes, and screening for liver cancer. If liver failure or liver cancer develops,
a liver transplant may be needed. After transplant, preventing hepatitis B infection in the new liver also helps prevent
hepatitis D from coming back.

Clinical trials and emerging therapies

Research on hepatitis D has accelerated in recent years, with multiple investigational therapies being studied. One therapy,
bulevirtide (Hepcludex), has been approved in parts of Europe, but it is not FDA-approved in the U.S. as of the most recent
publicly available drug-approval status listings. Meanwhile, other approaches (including monoclonal antibodies and additional
antiviral strategies) are moving through clinical trials.

If you have hepatitis Despecially chronic infectionask your clinician whether clinical trial participation makes sense for you.
Trials have strict criteria and safety monitoring, and your liver specialist can help interpret options realistically (and protect
you from “miracle cure” nonsense on the internet).

Prevention: The Best Hepatitis D Treatment Is Not Getting It

There is no hepatitis D vaccine. However, hepatitis D can be prevented by preventing hepatitis Bbecause without hepatitis B,
hepatitis D can’t establish infection. That’s why hepatitis B vaccination is the MVP of hepatitis D prevention.

Key prevention steps

• Get vaccinated for hepatitis B if you’re not already protected
• Don’t share needles or injection supplies
• Use condoms (latex or polyurethane) to reduce sexual transmission risk
• Don’t share personal items that may have blood (razors, toothbrushes, nail clippers)
• Use gloves if you must touch someone’s blood or open sores

Living With Hepatitis D: Practical Tips That Actually Help

Living with hepatitis D isn’t just lab values and medical acronyms. It’s also appointments, insurance calls, and learning
to protect your liver without turning your life into a spreadsheet (unless you love spreadsheets, in which case: live your truth).

Protect your liver day-to-day

• Avoid alcohol, which can worsen liver damage
• Review medications and supplements with a cliniciansome can harm the liver
• Eat in a liver-friendly way (think balanced meals, not “one weird hack”)
• Keep follow-up appointments for monitoring and cancer screening when recommended

Protect other people

People with hepatitis D should take precautions to avoid spreading infection: inform healthcare providers, avoid donating
blood or certain body fluids/tissues, and encourage partners to be tested and vaccinated for hepatitis B if needed.

Frequently Asked Questions

Can you get hepatitis D without hepatitis B?

No. Hepatitis D requires hepatitis B to infect a person and replicate.

Is there a hepatitis D vaccine?

Not currently. The hepatitis B vaccine helps prevent hepatitis D by preventing hepatitis B.

Is hepatitis D curable?

Some people clear acute infection, especially in coinfection scenarios. Chronic hepatitis D is more complex; treatment focuses on
suppressing viral activity when possible, preventing complications, and monitoring for liver damage. A liver specialist can explain
what “success” looks like in your specific situation.

Should everyone with hepatitis B be tested for hepatitis D?

Many experts recommend at least testing higher-risk individuals, and some advocacy organizations encourage broader testing among
everyone living with hepatitis B. If you have hepatitis B, it’s reasonable to ask your clinician whether HDV antibody and, if needed,
HDV RNA testing is appropriate for you.

Real-World Experiences: What People Often Describe (and What Helps)

When people talk about hepatitis D “in real life,” the story often starts the same way: they didn’t expect to be dealing with it.
Many individuals learn they have hepatitis B firstsometimes through routine screening, immigration health checks, prenatal labs,
or a work-up for fatigue or abnormal liver enzymes. Hepatitis D enters the conversation later, often when a clinician says,
“Your hepatitis B doesn’t fully explain what we’re seeing. Let’s test for HDV.”

The surprise test: A common experience is discovering that hepatitis D testing isn’t automatically done everywhere.
People describe bouncing between providers, seeing different opinions on whether they “need” HDV testing, and feeling confused by
mixed messages. What tends to help is bringing a simple, direct question to the appointment: “I have hepatitis Bshould I be tested
for hepatitis D with an antibody test, and if positive, an HDV RNA test?” Clear questions often lead to clear next steps.

The emotional roller coaster: People also describe a wave of emotionsfear, frustration, and sometimes guilt or stigma.
Hepatitis viruses are deeply misunderstood, and patients may worry others will assume the worst. Many find it helpful to remember:
hepatitis B and D are medical conditions, not moral scorecards. Support groups, trusted family members, or counseling can be surprisingly
valuableespecially when anxiety starts to hijack sleep and daily routines.

The “my labs are talking” phase: Another common experience is learning the language of liver care: ALT/AST, viral loads,
fibrosis staging, ultrasounds, elastography, and more. Some people feel empowered by tracking results; others feel overwhelmed.
A practical middle ground is to keep a simple health notebook (paper or digital) with three items: recent lab trends, medication list,
and your next two appointments. That’s enough structure to stay organized without turning your life into a medical TV series.

Treatment reality (and patience): Patients often describe disappointment when they learn there isn’t an FDA-approved,
HDV-specific medication in the U.S. right now. What helps is reframing the goal: “We’re building the strongest plan possible with the
tools available today, while keeping an eye on clinical trials and emerging therapies.” Many people do well with careful monitoring,
hepatitis B management, and complication preventioneven when treatment options feel limited.

Everyday wins: Finally, people frequently talk about the small choices that add up: cutting alcohol (or eliminating it),
checking supplements with a clinician, getting consistent sleep, eating balanced meals, and keeping follow-up testing on schedule.
None of these are glamorous. But they’re the “boring superhero” habits that can protect the liver over time. And yescelebrate the wins.
If you showed up for your appointment and asked the questions you were nervous to ask, that’s not small. That’s you taking the steering wheel.