Hepatitis E primary prevention
|
Hepatitis E Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Hepatitis E primary prevention On the Web |
|
American Roentgen Ray Society Images of Hepatitis E primary prevention |
|
Risk calculators and risk factors for Hepatitis E primary prevention |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Hepatitis E is a zoonosis that may be prevented by avoiding contact with the virus, and by immunization through vaccination. In order to avoid infection, measures such as appropriate sanitation, hygiene, and maintenance of the quality of the public water supplies should be observed. Also, thorough cooking of pork meat and avoidance of shellfish in endemic regions should be pursued. Blood transfusions represent a rare form of transmission that may be minimized with screening of blood donations. Two vaccines have been developed so far, and one of them has been approved in China. However, no further studies have been conducted regarding the distribution of the vaccine worldwide.
Prevention
Hepatitis E may be prevented by two ways:[1]
- Limiting exposure to the virus
- Immunization through vaccination
Hepatitis E is a zoonosis, therefore prevention of the disease should start by avoiding transmission of the virus from animals to humans. As almost all HEV infections are spread by the faecal - oral route, improving sanitation is the most important measure, along with good personal hygiene. High quality standards for public water supplies and proper disposal of sanitary waste have resulted in a low prevalence of HEV infections in many well developed societies.[2]
For travellers to high endemic areas, the usual elementary food hygiene precautions are recommended. These include:[3]
- Avoiding drinking water and/or ice of unknown purity
- Eating uncooked shellfish, uncooked fruits or vegetables that are not peeled or prepared by the traveller
- Cook pork thoroughly
- Avoid eating shellfish
Although rare, transmission has been reported through blood transfusions. Because infection is often asymptomatic, and most blood products are not tested for the presence of the virus, transmission of hepatitis E may be occurring unnoticed. This represents a concern for immunosuppressed patients, and for those with chronic liver disease, who are at risk of developing chronic hepatitis E. Therefore screening of blood products is considered a preventive measure.[1][4]
Guidelines for Epidemic Measures
The following measures should be observed in an epidemic situation:[3]
- Determination of the mode of transmission
- Identification of the population with an increased risk of infection
- Elimination of a common source of infection
- Improvement of sanitary and hygienic practices to eliminate faecal contamination of food and water
Vaccination
Patients who have recovered from HEV infection show immunity against HEV, which seems to offer life-long protection against the development of symptomatic hepatitis E.[5] Vaccination can also induce protective immunity. So far 2 vaccines have been developed:[6][1]
- The first vaccine showed 96% efficacy in Nepalese soldiers, after administration of 3 doses. It is expressed by insect cells. Unfortunately, no further developments were made to the vaccine.[7]
- A second vaccine has been developed and approved in China, with 94-100% efficacy in preventing acute hepatitis E. The vaccine is produced by bacterial cells (E. coli), does not show relevant side-effects, and is safe for administration on pregnant women. Further studies are required in high-risk groups, such as immunocompromised and end-stage liver disease patients.[8]
References
- ↑ 1.0 1.1 1.2 Kamar N, Bendall R, Legrand-Abravanel F, Xia NS, Ijaz S, Izopet J; et al. (2012). "Hepatitis E." Lancet. 379 (9835): 2477–88. doi:10.1016/S0140-6736(11)61849-7. PMID 22549046.
- ↑ Mandell, Gerald (2010). Mandell, Douglas, and Bennett's principles and practice of infectious diseases. Philadelphia, PA: Churchill Livingstone/Elsevier. ISBN 0443068399.
- ↑ 3.0 3.1 "Hepatitis E".
- ↑ Hoofnagle JH, Nelson KE, Purcell RH (2012). "Hepatitis E." N Engl J Med. 367 (13): 1237–44. doi:10.1056/NEJMra1204512. PMID 23013075.
- ↑ Zhu FC, Zhang J, Zhang XF, Zhou C, Wang ZZ, Huang SJ; et al. (2010). "Efficacy and safety of a recombinant hepatitis E vaccine in healthy adults: a large-scale, randomised, double-blind placebo-controlled, phase 3 trial". Lancet. 376 (9744): 895–902. doi:10.1016/S0140-6736(10)61030-6. PMID 20728932.
- ↑ Wedemeyer H, Pischke S, Manns MP (2012). "Pathogenesis and treatment of hepatitis e virus infection". Gastroenterology. 142 (6): 1388–1397.e1. doi:10.1053/j.gastro.2012.02.014. PMID 22537448.
- ↑ Shrestha MP, Scott RM, Joshi DM, Mammen MP, Thapa GB, Thapa N; et al. (2007). "Safety and efficacy of a recombinant hepatitis E vaccine". N Engl J Med. 356 (9): 895–903. doi:10.1056/NEJMoa061847. PMID 17329696.
- ↑ Wedemeyer H, Pischke S (2011). "Hepatitis: Hepatitis E vaccination--is HEV 239 the breakthrough?". Nat Rev Gastroenterol Hepatol. 8 (1): 8–10. doi:10.1038/nrgastro.2010.207. PMID 21212772.