Hepatitis E Vaccine Called Highly Effective

THURSDAY, March 1 (HealthDay News) -- A new vaccine may safely protect against hepatitis E, a virus prevalent in developing countries.

In a study of 2,000 healthy adults from Nepal, researchers found that the vaccine was 96 percent effective in preventing hepatitis E infection.

"This is the first new hepatitis vaccine strain for which efficacy has been shown since 1992, and it's very well tolerated. I would say this vaccine is a home run," said the study's lead author, Dr. Bruce Innis, vice president of clinical research and development for GlaxoSmithKline, the vaccine's manufacturer.

Results of the study are published in the March 1 issue of theNew England Journal of Medicine. The study was funded by GlaxoSmithKline, U.S Army Medical Research and Material Command, and the National Institute of Allergy and Infectious Diseases.

Hepatitis E is an infectious disease that's generally spread through fecal contamination of food or water, according to the World Health Organization (WHO). It's often a self-limiting illness, and most people recover with no long-term consequences. However, women in their third trimester of pregnancy are particularly susceptible to hepatitis E and have a mortality rate as high as 20 percent from the infection.

The hepatitis E virus is relatively uncommon in the United States but is prevalent in other areas of the world. According to background information in the study, it's estimated that as many as one-third of the world's population has been infected with hepatitis E. And, in some countries, such as India, that rate may be as high as 60 percent.

Symptoms of hepatitis E develop from three to eight weeks after exposure, with an average incubation period of 40 days, according to WHO. Those most at risk include people between the ages of 15 and 40, pregnant women and people traveling to countries where hepatitis E is common, according to the U.S. Centers for Disease Control and Prevention. Symptoms of the disease include jaundice, abdominal pain, fatigue, loss of appetite, dark urine, nausea and vomiting.

To test the efficacy of the newly developed recombinant vaccine, 2,000 healthy adults -- 99.6 percent of them male -- from Nepal were randomly selected to receive either the vaccine or a placebo shot. All of the study volunteers were part of the Nepalese army.

The vaccine was administered in three doses, with the second dose given after a month and the third given at six months. The average follow-up time was 804 days. Innis said that political turmoil in Nepal added to the challenge of conducting a study in a country where there is little industrial development.

At the end of the study, complete follow-up data was available on 1,794 study volunteers -- 898 who received the vaccine and 896 from the placebo group.

Hepatitis E developed in 69 people during the study period. Sixty-six of those infected were from the placebo group.

The vaccine's efficacy was 95.5 percent, according to the study.