WEDNESDAY, March 4, 2015 (HealthDay News) -- A new vaccine for hepatitis E provides protection from the virus for at least 4.5 years, according to Chinese researchers.
Although hepatitis E is relatively rare in the United States, it's a leading cause of serious liver problems in the developing world. Hepatitis E is spread through contaminated water and through person-to-person contact, the researchers said.
"The hepatitis E vaccine was licensed in China in 2011 and is the only hepatitis E vaccine in the world," said lead researcher Dr. Ning-Shao Xia, a professor in the department of biology at Xiamen University.
What hasn't been known is how long the vaccine continues to offer protection against hepatitis E, the researchers said.
"Hepatitis E is one of the most common causes of acute hepatitis. Outbreaks occur now and then in areas with poor sanitation. Hepatitis E is the most life-threatening disease for pregnant women in poor areas," Xia said.
But, Xia said these findings show that hepatitis E is now a vaccine-preventable disease.
The report was published March 5 in the New England Journal of Medicine.
Every year about 20 million people are infected with hepatitis E, according to the World Health Organization. Of those, more than 3 million will develop acute hepatitis E disease, and almost 57,000 will die.
While not common in the United States, hepatitis E infections occur more frequently in places such as Bangladesh, India, Pakistan, Mexico and parts of Africa and China, said Dr. John Ward. He is director of the division of viral hepatitis at the U.S. Centers for Disease Control and Prevention and co-author of an accompanying journal editorial.
Hepatitis E is spread in areas where sanitation is poor. "Many people get sick from this virus, but only 1 to 3 percent die from it, except [among] pregnant women," Ward said. "Pregnant women have about a one in five chance of dying. There is no treatment for hepatitis E."
Hepatitis E can lead to liver failure and death, he added.
The good news, Ward said, is that "we now have a hepatitis E vaccine that can protect people for an extended period."
Ward added that the vaccine is safe and effective. The next job is deciding who should get vaccinated and how that could be funded. "We don't know the price of the vaccine and its ability to be produced in large quantities," he said.
One place where the vaccine is needed is in refugee camps, where outbreaks of hepatitis E often occur, Ward said. "The vaccine can be considered most immediately in these humanitarian crisis situations," he said.
Hepatitis E generally occurs in the United States in travelers coming from areas where it is highly endemic, Ward said. A form of hepatitis E circulates in Europe and the United States, but it does not cause serious illness, he said. Thus, Americans aren't candidates for the vaccine, he added.
For the study, Xia's team randomly assigned more than 56,000 healthy adults, aged 16 to 65, to get three shots of the hepatitis E vaccine. At the same time, a similar number of adults were injected with the hepatitis B vaccine (the "control" group).
During the 4.5 years of follow-up, 60 people developed hepatitis E. Seven were among those who received the hepatitis E vaccine, and 53 cases developed in those given the hepatitis B vaccine, the researchers found.
Almost 90 percent of those who received three doses of the hepatitis E vaccine maintained antibodies against the virus for at least 4.5 years, the study authors said.
For more on hepatitis E, visit the U.S. Centers for Disease Control and Prevention.