Hepatitis E is liver inflammation caused by hepatitis E virus (HEV) — the most common cause of acute viral hepatitis globally, responsible for approximately 20 million infections per year. Most infections are self-limiting (2-6 weeks) in non-pregnant healthy adults, causing jaundice, fatigue and nausea that resolve without treatment. However, HEV causes devastating disease in two groups: pregnant women (20-25% mortality from fulminant liver failure) and immunocompromised individuals (chronic hepatitis progressing to cirrhosis).

How is hepatitis E transmitted?

Two distinct transmission routes: Genotype 1 and 2 (human strains) — via faecally contaminated drinking water, person-to-person contact, and contaminated food. These cause large waterborne outbreaks in areas with poor sanitation — predominantly in South Asia, East Africa and Central Asia. Genotype 3 and 4 (zoonotic strains from pigs) — via consumption of undercooked pork or game (wild boar) in high-income countries. Gt3/4 cause sporadic cases and chronic infection in immunocompromised hosts.

Why is hepatitis E so dangerous in pregnancy?

Gt1 HEV infection in the third trimester causes fulminant hepatic failure in approximately 20-25% of cases — a rapidly fatal condition involving massive liver necrosis, coagulopathy (inability to form blood clots), encephalopathy, renal failure and death. Maternal mortality reaches 20-25% in clinical cases (much higher than in non-pregnant adults, where mortality is <1%). Near-total fetal/neonatal loss occurs in severe maternal disease. The mechanism of this unique susceptibility is not fully understood but may involve immune modulation of pregnancy and hormonal effects on viral replication.

Is there a vaccine for hepatitis E?

An effective vaccine exists but is not globally available. HEV239 (Hecolin, Innovax/Xiamen Innovax Biotech) — a recombinant protein subunit vaccine — showed >95% efficacy in two large Phase 3 trials in China and has been licensed in China since 2012 and Pakistan since 2020. However, it has not yet received WHO prequalification — preventing its procurement through UNICEF and other international procurement agencies for use in outbreak response in LMICs. WHO is actively pursuing prequalification of HEV vaccines as a global health priority.

How does hepatitis E differ from hepatitis A?

Both hepatitis A and hepatitis E are transmitted faecal-orally via contaminated water or food and cause self-limiting jaundice in most patients. Key differences: HEV uniquely causes fulminant hepatitis in pregnancy (not seen with HAV); HEV causes chronic infection in immunocompromised patients (HAV does not); HEV is a zoonotic disease (pig reservoir for Gt3/4) while HAV is not; there is an effective globally available HAV vaccine on WHO prequalification list, while HEV vaccine is not yet prequalified.

High-risk groups for severe HEV disease: pregnant women (particularly 3rd trimester — highest risk of fulminant disease); solid organ transplant recipients and others on immunosuppression (chronic HEV risk from Gt3/4); HIV-positive individuals with low CD4 counts; people with pre-existing liver disease (cirrhosis from any cause); travellers to endemic areas. High-risk settings for HEV outbreaks: refugee camps; post-disaster populations with disrupted water systems; overcrowded settings with shared water supplies.

How are HEV outbreaks managed?

Outbreak control (Gt1/2): improving water supply quality (chlorination, filtration); promoting hand hygiene and sanitation; oral rehydration; supportive care for jaundiced patients; early identification of pregnant women for close monitoring; and if available, ring vaccination with HEV239. Individual treatment: no specific antiviral for acute HEV in otherwise healthy patients (self-limiting). For chronic HEV in transplant patients: ribavirin (off-label); reduction of immunosuppression (if clinically feasible).

What is the disease burden of hepatitis E?

WHO estimates 20 million HEV infections per year globally — predominantly in South Asia (India is estimated to have approximately 60% of the global HEV burden), East Africa and Central Asia. Approximately 44,000 deaths per year — predominantly from pregnancy-related fulminant hepatitis. HEV in pregnancy accounts for a significant proportion of maternal deaths from acute liver failure in endemic regions. The burden is dramatically underreported because many cases are misdiagnosed as other hepatitis causes or undifferentiated febrile illness.

How does GMJ News cover hepatitis E?

GMJ News covers WHO hepatitis E burden data, pregnancy risk evidence, HEV239 vaccine development and WHO prequalification progress, chronic HEV in immunocompromised patients, and HEV in the Georgia/Caucasus context. Hepatitis E is relevant to PHIG's viral hepatitis and maternal health priorities.

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Hepatitis E

Q: Is there a vaccine for hepatitis E?

An effective vaccine exists but is not globally available. HEV239 (Hecolin, Innovax/Xiamen Innovax Biotech) — a recombinant protein subunit vaccine — showed >95% efficacy in two large Phase 3 trials in China and has been licensed in China since 2012 and Pakistan since 2020. However, it has not yet received WHO prequalification — preventing its procurement through UNICEF and other international procurement agencies for use in outbreak response in LMICs. WHO is actively pursuing prequalification of HEV vaccines as a global health priority.

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Hepatitis E — caused by hepatitis E virus (HEV) transmitted primarily through faecally contaminated drinking water — causes an estimated 20 million infections and 44,000 deaths per year, making it the leading cause of acute viral hepatitis globally and a major public health problem in areas of poor sanitation (WHO). HEV infection during pregnancy is particularly dangerous — causing fulminant hepatic failure and maternal mortality of 20-25% in the third trimester. An effective recombinant HEV vaccine (HEV239/Hecolin) has been licensed in China since 2012 but has not yet been approved elsewhere or prequalified by WHO.

Key messages

20 million infections/year

Hepatitis E — caused by hepatitis E virus (HEV), transmitted primarily through contaminated water — causes an estimated 20 million infections and 44,000 deaths per year globally, making it the most common cause of acute viral hepatitis worldwide (WHO).

Devastating in pregnancy

HEV infection in the third trimester of pregnancy causes fulminant hepatic failure in approximately 20-25% of cases — with maternal mortality of 20-25% and near-universal fetal/neonatal loss in fulminant disease. This makes hepatitis E one of the most dangerous infections in pregnancy.

Two distinct transmission patterns

Genotype 1 and 2 HEV (in humans only) spread via contaminated water in LMICs — causing epidemics in areas with poor sanitation. Genotype 3 and 4 HEV (zoonotic, from pigs) cause sporadic cases in high-income countries — from eating undercooked pork or game.

Effective vaccine available but not globally

HEV239 (Hecolin) — a recombinant HEV vaccine with >95% efficacy — has been licensed in China since 2012 and is approved in Pakistan. It has NOT been WHO-prequalified, preventing access through international procurement. WHO approval would enable use in outbreak settings.

Immunocompromised at high risk

Genotype 3 HEV causes chronic hepatitis in immunocompromised patients (transplant recipients, HIV, haematological malignancies) — progressing to cirrhosis within 2-5 years. Ribavirin treatment (off-label) can clear chronic infection; PEGylated interferon is second-line.

No approved antiviral for pregnancy

There is no approved antiviral treatment for acute hepatitis E in pregnancy — the clinical scenario with the most severe outcomes. Ribavirin is teratogenic and therefore contraindicated. Supportive care, ICU management of coagulopathy and liver failure, and delivery decisions are the only options.

Key statistics

20M

HEV infections/year

WHO

44K

hepatitis E deaths/year

WHO

20-25%

maternal mortality in 3rd trimester fulminant HEV

WHO

>95%

efficacy of HEV239 vaccine

WHO/Lancet

2012

year HEV239 licensed in China

China NMPA

WHO-prequalified HEV vaccines (as of 2024)

WHO

Hepatitis E incidence per 100,000 population by region — WHO/modelled

Source: WHO estimates. South Asia and East Africa carry the largest HEV waterborne disease burden.

Glossary of key terms

Hepatitis E virus (HEV)
WHOA positive-sense ssRNA virus (genus Orthohepevirus A) — four main genotypes cause human disease. Gt1 and Gt2 (human only — epidemic in South Asia, Africa via contaminated water); Gt3 and Gt4 (zoonotic — from pigs; sporadic in high-income countries via undercooked pork).

HEV in pregnancy (fulminant hepatitis)
WHOPregnant women (particularly third trimester) infected with Gt1 HEV have a 20-25% risk of fulminant hepatic failure — rapid, massive liver necrosis causing coagulopathy, encephalopathy, renal failure and death. The mechanism of this unique susceptibility is poorly understood; immune-mediated and hormonal factors are implicated.

HEV239 (Hecolin)
WHO/ChinaA recombinant protein subunit HEV vaccine — producing HEV ORF2 antigen from E. coli. Two large Phase 3 trials in China showed >95% efficacy. Licensed in China (2012) and Pakistan. Not yet WHO-prequalified — limiting its use in international outbreak response.

Chronic hepatitis E
WHO/EASLHEV Gt3 infection becoming chronic (>3 months) in immunocompromised patients — particularly solid organ transplant recipients on immunosuppression and HIV patients with low CD4 counts. Progresses to cirrhosis within 2-5 years in approximately 10-15% of chronic cases. Treated with ribavirin (off-label).

Ribavirin for HEV
WHO/EASLRibavirin (off-label) is effective for chronic HEV in transplant patients — achieving sustained virological response in approximately 80% of cases with 3 months of treatment. Contraindicated in pregnancy (teratogenic). There is no approved antiviral for acute HEV in pregnant women — the most clinically urgent treatment gap.

Icteric hepatitis
WHOHepatitis presenting with jaundice (yellowing of skin and eyes from elevated bilirubin) — the typical presentation of acute HEV. Accompanied by right upper quadrant pain, dark urine, pale stools, nausea and fatigue. Self-limiting in most non-pregnant adults; severe in pregnant women and immunocompromised patients.