MONDAY, Aug. 23, 2010 (HealthDay News) -- A new vaccine designed to protect individuals from becoming infected with the hepatitis E virus appears to be virtually foolproof, ongoing Chinese research indicates.
After analyzing results from the third phase of their study, a team of scientists led by Dr Ning-Shao Xia, from the Institute of Diagnostics and Vaccine Development in Infectious Diseases at Xiamen University in Xiamen, found that three standard doses of the so-called "HEV239" vaccine, given over a six-month period, afforded patients full immunity from the disease up to a year after the final innoculation, without prompting any serious side effects.
What's more, even an incomplete regimen of just two doses of the vaccine applied within a one-month period appears to protect against infection equally well, the researchers found.
The observations, reported in the Aug. 23 online issue of The Lancet, are based on data from more than 110,000 healthy male and female participants between the ages of 16 and 65, half of whom were given the vaccine.
The authors noted that hepatitis E has already infected about one-third of the world's population, primarily in developing nations. The virus spreads via food or water contaminated by feces from an infected person.
Although not a chronic illness, hepatitis E can pose a serious health challenge to certain groups of people, such as those with chronic liver disease and pregnant women. Overall, between 1 percent to 3 percent of those infected die; among pregnant women that figure rises to between 5 percent and 25 percent.
Although they stress that further study is needed, the Chinese team said the findings suggest that "the vaccine [is] well-tolerated and efficacious for a general adult population", and should be prioritized for patients battling chronic liver disease.
Dr. Eugene Schiff, director of the Center for Liver Disease at the University of Miami School of Medicine, said that while he was not entirely surprised by the apparent success of the current vaccine effort, he viewed it as a long-needed critical step forward.
"Even though this is a virus that is transmitted like hepatitis A, by ingestion of contaminated food and water, we don't see it much in the U.S," he noted. "But it is quite common in many parts of the world, particularly where there is flooding, like, for example, in Bangladesh. And while it is usually self-limited and does not become chronic, it can be very serious in certain groups of people like pregnant women and older persons."
"So, while in the U.S. you wouldn't want to give a vaccine to everyone, you certainly would want to give it to anyone who was going to travel to an endemic area, as well as to people living in endemic areas," Schiff added.
"So, I'm pleased to see these findings, and I would say this is an important piece of work," he said. "And because it's a large study I don't believe they're overstating their case. The vaccine appears to be highly effective and safe, and it will certainly be utilized extensively in those areas of the world where hepatitis E is endemic."
For more on hepatitis E, visit the National Digestive Diseases Information Clearinghouse.