Hepatitis E Virus and the HEV vaccine

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Copyright 2012 - Kris Heeter, Ph.D.


The Hepatitis E virus (HEV) is capable of causing an acute or chronic infection that can lead to an inflammatory liver disease.

There are four major Hep E variants or genotypes have been described. HEV genotypes 1 and 2 are typically found to infect humans whereas genotypes 3 and 4 have been found in both humans and several animal species. A majority of the animal infections are found in swine.

Globally, HEV is the most common cause of acute viral hepatitis.


Transmission and Outbreaks of Hepatitis E

Transmission of the Hepatitis E virus to humans generally happens when someone drinks water that is contaminated with feces containing the virus.

Hepatitis E viral infections in humans have been considered rare in most industrialized countries, including the United States. However, in these countries, there have been reports of acute and chronic HEV infections among transplant recipients and other immunocompromised individuals like those with HIV.

Transmission through blood between humans is rare and only a few cases of Hepatitis E have resulted from person-to-person contact. Research suggests that this virus cannot be spread through sexual activity.

Major HEV outbreaks typically occur in regions of the world where sanitation is poor and where there is excessive rain or flooding.

For example, in countries like Nepal, the virus can cause annual outbreaks during the rain and flooding season. During this season, it is a leading cause of hospitalization of all age groups.


Acute vs. Chronic Hepatitis E

An acute Hepatitis E virus infection can occur as either as epidemic outbreak or as sporadic cases. These are typically short-lived infections. Epidemic outbreaks are more common in countries with flooding and poor sanitation whereas sporadic cases occur in industrialized countries.

Chronic HEV infections are less common and are long-term. These have been reported in immunosuppressed patients, those with HIV, and those with hematological malignancies. Recently, a case has been reported in a patient with leukemia.


HEV vaccine

Once a person is infected with HEV, there are no drug treatments available.

The typical medical course of action is rest, plenty of fluids, and a healthy diet. According the National Institute of Allergy and Infectious Disease (NIAIC), it is recommended that those infected avoid any over-the-counter or prescription medication that could damage the liver. Drinking alcohol during the recovery period could compound the problem and increase the risk for liver damage.

A HEV vaccine has been developed and has proven to be safe and highly effective. According the NIAIC, three doses are 96% effective and two doses are 87% effective at preventing the disease.


Related References

Song Y. (2010). Studies of hepatitis E virus genotypes. Indian J Med Res. 2010 November; 132(5): 487–488.

Nelson et al. (2011). The epidemiology of hepatitis E virus infections in developed countries and among immunocompromised patients. Expert Rev Anti Infect Ther. 2011 Dec;9(12):1133-48.

Kamar et al. (2012). Hepatitis E. Lancet. 2012 Jun 30;379(9835):2477-88. Epub 2012 Apr 30.

Gauss et al.. (2012). Chronic hepatitis E virus infection in a patient with leukemia and elevated transaminases: a case report. J Med Case Rep. 2012 Oct 2;6(1):334. doi: 10.1186/1752-1947-6-334.


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Comments 9 comments

eHealer profile image

eHealer 4 years ago from Las Vegas

Kris, this is extremely interesting. Years back, we had a kidney transplant patient that had contracted HEV, it was the only case I had ever seen. For a few weeks, it was identified as the the usual CMV, until they did a PCR. It resolved in couple of months, but the patient was taking Cyclovir and it created a real myriad of symptoms. Thanks for this great information!


Kris Heeter profile image

Kris Heeter 4 years ago from Indiana Author

@eHealer - thanks for stopping by. It's amazing how PCR can now resolve things like this. It's so quick and easy now and doesn't leave doctors second guessing!


eHealer profile image

eHealer 4 years ago from Las Vegas

Hello, Kris, yes, PCR has knocked my socks off a few times! Even after the HEV was resolved, the PCR was performed to confirm the clinical results. I believe it is the discovery of the century, and so few people get to appreciate the applications of PCR!


Kris Heeter profile image

Kris Heeter 4 years ago from Indiana Author

eHealer - yes, I agree. PCR is now used in so many daily applications that most of the population isn't aware of. I hired someone a few years ago who had been technician whose previous job was to do PCR on swabs taken a major events across the country with the whole purpose being to identify infectious agents used in bioterrorism. I had no idea that there was and still is this constant round the clock check at such an in depth level.


MargaritaEden profile image

MargaritaEden 4 years ago from Oregon

How scary, I had no idea there is already Hep E discovered, thank you for sharing this info, very informative.


Kris Heeter profile image

Kris Heeter 4 years ago from Indiana Author

@MargaritaEden - thanks for stopping by and I glad you found it informative.


calculus-geometry profile image

calculus-geometry 3 years ago from Germany

Interesting stuff, I didn't know there was Hep E either. What is the naming convention for different types of Hepatitis?


Kris Heeter profile image

Kris Heeter 3 years ago from Indiana Author

@ Calculus-geomtry - that's a great question. I look into it...


joedolphin88 profile image

joedolphin88 2 years ago from north miami FL

Wow this is a powerful read, didn't even know there was more then a b and c.

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