Prevention depends entirely on avoiding the consumption of non-approved food, water and ice, Kester added. This involves treatment, storage and distribution of water in accordance with current DoD water-purification guidelines, which will inactivate the virus. “If drinking water is to be procured from local vendors, stringent inspection, approval and monitoring are essential,” said Kester. In addition, he said, hepatitis E prevention requires that strict limits be placed on the consumption of non-approved local food or drinking local water when there is deployment in an area endemic for hepatitis E.

“Approved” local food and water (including ice) sources are those which have been inspected by the U.S. Food and Drug Administration, U.S. Department of Agriculture, U.S. Public Health Command or other preventive medicine assets “and have been found to conform to the stringent standards for food quality and safety,” noted Lt. Col. Donald Lundy, Environmental Science staff officer, U.S. Army Proponency Office for Preventive Medicine.

“If water is procured from local vendors (e.g., commercially-acquired/contracted bottled water) or from fixed facilities, an assessment of risks (DoD Food and Water Risk Assessment) and the same stringent standards for water safety — system security, treatment effectiveness, and overall water quality — apply,” Lundy explained.

Vaccine Research Abandoned

Several years ago, the Army collaborated with GlaxoSmithKline in conducting a clinical trial of a vaccine, based on technology developed by the National Institutes of Health and produced by the pharmaceutical company.

“At that time, the vaccine was of interest because of the potential threat to U.S. forces posed by the hepatitis E virus,” recounted Kester. Preventive measures have been so successful during recent deployments; however, the requirement for the vaccine has dropped to low on the list of the military infectious diseases medical research and development programs.

“While hepatitis E exists in many areas of the world, and the vaccine was highly efficacious in the proof-of-concept study, the pharmaceutical company determined that scale-up and manufacture of the vaccine would be too costly and discontinued the effort,” Kester said.

Subsequently, Glaxo suspended its research. “We have made efforts to establish public partnerships and collaborations with manufacturers to support and co-finance the development of an HEV vaccine for use where HEV is endemic,” a Glaxo spokesperson told U.S. Medicine. “Given the present lack of consensus on whether immunization against HEV should become a public-health priority and the emergence of a more advanced HEV vaccine candidate produced by another manufacturer, GSK has decided to focus its research on other programs concerning acknowledged public-health priorities.”

In any event, Kester said, it’s unlikely that, if a vaccine became available, it would be a standard military immunization for U.S. forces. “More likely it would be used selectively in deploying units based on the strength of the threat in the deployment area,” he explained.

Meanwhile, other groups around the world are working on hepatitis E vaccines. A recent report from a Chinese group on their Phase III trial of a recombinant vaccine showed that none of the individuals who received the vaccine developed hepatitis E.

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