People in countries with poor sanitation are highly vulnerable to the disease

Flickr/United Nations Development Programme

Chinese scientists have developed a promising vaccine against hepatitis E that they say safely protects most adults from the infectious disease, which kills many people in countries with poor sanitation.

The researchers' HEV 239 vaccine was 100 per cent effective in a phase III trial on healthy adults of both sexes. The results were published online in The Lancet last week (23 August).  It is the first vaccine against the disease to reach this stage.

In the trial, participants were randomly assigned three doses of either HEV 239 or a placebo vaccine. Two doses were given within a month, with the third in the sixth month. The trial lasted a further 13 months. At the end of this period, none of the patients given the HEV 239 vaccine contracted hepatitis E, compared with 15 in the placebo group. "Adverse effects attributable to the vaccine were few and mild," the authors wrote.

China's State Food and Drug Administration is now examining the vaccine. "It might take months or more than a year for the government to complete the process," said Xia Ningshao, lead author and director of the Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University.

Hepatitis E is a leading cause of acute hepatitis in Africa, Mexico and South Asia. "In India, more than 50 per cent of the clinical acute hepatitis cases are infected with this virus," Xia says. "Our vaccine will definitely benefit the people in these countries and whoever travels there."

Scott Holmberg, an expert on viral hepatitis with the US Centers for Disease Control and Prevention, agreed the vaccine may be important for tackling hepatitis E outbreaks while developing countries improve their sanitation infrastructure.

But he pointed out that the vaccine needs further trials for pregnant women and infants, who are "more likely to die from hepatitis E infection but were not included in the study".

Up to a quarter of pregnant women who catch hepatitis E die from it, and survivors have high rates of spontaneous abortion and stillbirth.

"There's no reason at present to think the vaccine will not work for these special populations but until they are vaccinated it will remain a question mark," said Holmberg, adding that researchers do not yet know how long the vaccine remains effective.

Patients with other chronic liver diseases, a group in particular need of a vaccine, were also excluded from the study.

"Additional research is needed to assess the benefit of HEV 239 (in this regard)" say the authors.   

Link to full study in The Lancet*