[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [RNA hepatitis viruses](https://durgical.com/en/microbiology/groups/rna-hepatitis-viruses/) › Hepatitis D virus

[Microbiology](https://durgical.com/en/microbiology/) · [RNA hepatitis viruses](https://durgical.com/en/microbiology/groups/rna-hepatitis-viruses/)

# Hepatitis D virus

- Virus
- Enveloped
- Exam priority: medium

An incomplete virus that only infects people who have hepatitis B. It causes the most severe form of chronic viral hepatitis.

Updated 2026-11-01

Also called: HDV, delta virus, delta agent

## Key points

- Defective virus: uses hepatitis B HBsAg as its envelope
- Coinfection usually clears; superinfection worsens and becomes chronic
- The most severe form of chronic viral hepatitis
- Vaccinating against hepatitis B prevents hepatitis D

## At a glance

**Shape**
Spherical

**Genome**
Circular, single-stranded, negative-sense RNA

**Envelope**
Enveloped

**Family**
Kolmioviridae, genus Deltavirus

**Size**
About 36 nm

## Morphology

- The smallest RNA genome among animal viruses, viroid-like
- Encodes only the delta antigen; its envelope is hepatitis B surface antigen (HBsAg)

## Transmission

- Blood and body fluids: shared needles, transfusions, sexual contact
- Household spread in hyperendemic areas
- Always needs simultaneous or prior hepatitis B infection

**Reservoir:** Humans infected with hepatitis B

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Virulence factors

- Relies on HBsAg to assemble particles and infect new hepatocytes
- Superinfection of a chronic B carrier speeds fibrosis and cirrhosis
- Classified as a human carcinogen

## Diseases it causes

- Hepatitis D by coinfection (together with hepatitis B) or superinfection (in a chronic hepatitis B carrier) [Viral hepatitis →](https://durgical.com/en/conditions/viral-hepatitis/)

## Clinical picture

- Coinfection: acute hepatitis that usually resolves; under 5% become chronic
- Superinfection: severe, sometimes fulminant hepatitis with a high rate of chronicity
- Faster progression to cirrhosis, decompensation and hepatocellular carcinoma than hepatitis B alone

## Diagnosis

- Test for anti-HDV antibodies in everyone who is HBsAg-positive
- HDV RNA confirms active infection
- Positive anti-HBc IgM suggests coinfection; negative with chronic HBsAg suggests superinfection

## Treatment

Options are limited: pegylated interferon alfa, which works in a minority, and bulevirtide, an entry inhibitor approved in some countries. Nucleoside analogues against hepatitis B do not act on hepatitis D.

Drug class only; doses and regimens are set by the clinician from the current guideline.

## Prevention

- Hepatitis B vaccine prevents coinfection
- Blood safety and safe injections
- Harm reduction for people who inject drugs

**Vaccine:** No vaccine of its own; the hepatitis B vaccine in the PAI protects indirectly.

## In Colombia

The Amazon basin is a hyperendemic area for hepatitis D in South America, and in Colombia severe outbreaks were described in Indigenous communities of the Sierra Nevada de Santa Marta and the Amazon; universal hepatitis B vaccination reduced its impact.

## Memory aid

D is for "Dependent": without hepatitis B's coat it cannot go out.

## Test yourself

Think of the answer, then tap the question to see it.

## Which hepatitis B protein does hepatitis D virus need?

Hepatitis B surface antigen (HBsAg), which forms its envelope.

## How do coinfection and superinfection with HDV differ in outcome?

Coinfection usually resolves; superinfection of a chronic B carrier tends to chronicity and faster cirrhosis.

## How is hepatitis D prevented at population level?

With the hepatitis B vaccine, because without hepatitis B there is no hepatitis D infection.

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## Related

- [Hepatitis C virus](https://durgical.com/en/microbiology/hepatitis-c-virus/)
- [Hepatitis B virus](https://durgical.com/en/microbiology/hepatitis-b-virus/)

## Related conditions

- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

[← Back to the group: RNA hepatitis viruses](https://durgical.com/en/microbiology/groups/rna-hepatitis-viruses/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Hepatitis D](https://www.who.int/news-room/fact-sheets/detail/hepatitis-d) (World Health Organization (WHO), 2025); [Appendix A: Type and Duration of Precautions Recommended for Selected Infections and Conditions](https://www.cdc.gov/infection-control/hcp/isolation-precautions/appendix-a-type-duration.html) (CDC, 2024).

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Representative model, for educational purposes only.

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