Are Hepatitis D and E Common?
Hepatitis E is extremely common globally with an estimated 20 million infections annually, while hepatitis D affects approximately 12 million people worldwide—making both significant public health concerns, though their prevalence varies dramatically by geography and population.
Hepatitis E Prevalence
Hepatitis E is one of the most common causes of acute hepatitis worldwide 1. The global burden is substantial:
- 20 million infections per year with 3 million symptomatic cases and 70,000 deaths annually 1
- In Europe alone, at least 2 million locally acquired HEV infections occur yearly 1
- The disease is underestimated due to poor sensitivity of older diagnostic assays—one study found true seroprevalence was underestimated by 100% when validated assays were used 1
Geographic Distribution
HEV epidemiology differs markedly between regions:
- Endemic areas (Asia, Africa, Mexico): HEV genotypes 1 and 2 cause large waterborne outbreaks affecting thousands, with sporadic cases interspersed. Ongoing outbreaks persist in African refugee camps 1
- High-income countries (Europe, North America): HEV genotypes 3 and 4 are endemic as zoonotic infections transmitted primarily through pork consumption. In France, 99% of 2,000 laboratory-confirmed cases in 2014 were locally acquired 1
Important caveat: The true global burden requires urgent updating, as current estimates exclude zoonotic HEV in high-income countries and relied on insensitive older assays 1.
Hepatitis D Prevalence
Hepatitis D affects approximately 12 million people globally 2, 3, though estimates range up to 72 million 2. Among HBsAg-positive individuals:
- 4.5% overall prevalence in the general HBsAg-positive population 3
- 16.4% prevalence among those attending hepatology clinics 3
- This translates to 0.16% of the world's general population 3
High-Risk Populations
HDV prevalence is dramatically higher in specific groups:
- People who inject drugs (PWID)
- HIV-HBV coinfected individuals (consistently higher rates across Europe) 4
- Men who have sex with men
- Commercial sex workers
- Hemodialysis recipients 3
Geographic Hotspots
Highest prevalence regions include Mongolia, Republic of Moldova, Western and Middle Africa, Greenland, Norway, Romania, Sweden, and Italy 4, 3. Eastern Europe and the Mediterranean are high-endemicity zones 4.
Critical consideration: HDV is significantly underdiagnosed—only 20-50% of infected individuals have been identified due to lack of awareness and limited diagnostic access 2. Recent WHO 2024 guidelines now recommend universal anti-HDV testing for all HBsAg-positive individuals 5, 6.
Clinical Significance
Both infections carry substantial morbidity and mortality:
Hepatitis E:
- 25% mortality in pregnant women (genotypes 1 and 2) due to fulminant hepatic failure 1
- Up to 70% mortality in patients with underlying chronic liver disease who develop HEV superinfection 1
Hepatitis D:
- 18% of cirrhosis cases and 20% of hepatocellular carcinoma cases among HBsAg-positive individuals are attributable to HDV 3
- 30-70% have cirrhosis at diagnosis, with more than 50% dying of liver disease within 10 years in older studies, though recent data suggest more variable progression 2
The answer is unequivocal: both hepatitis D and E are common and represent major global health burdens that are currently underrecognized and undertreated.