A small trial of a hepatitis E vaccine developed in China showed that immunization was an effective strategy for curbing an outbreak at a refugee camp in South Sudan in 2022, an international research team reported recently in The Lancet Infectious Diseases.

The Hecolin vaccine was developed in China and was licensed in some countries in 2011 and is typically given as three doses. The World Health Organization (WHO) in 2015 recommended its use in outbreak settings.
Senior study author Andrew Azman, PhD, an epidemiologist at the University of Geneva/Geneva University Hospitals (UNIGE-HUG) Centre for Emerging Viral Diseases, said in a press release from the school that hepatitis E leads to about 50,000 deaths each year and that the displaced persons camp where the trial was conducted regularly experienced outbreak from the virus, likely due to poor sanitation and frequent flooding, which contribute to the spread of multiple waterborne diseases.
First use in an outbreak outside China
Until the trial, the Hecolin vaccine hadn't been used outside of China. The vaccine trial targeted people ages 16 and older. The case-control study included 859 people with suspected hepatitis E infections, of whom 201 met trial eligibility criteria. Twenty-one had lab confirmed hepatitis E infections. Of those, 10 (48%) were unvaccinated, compared with 33 (27%) of 121 matched controls. The unadjusted two-dose vaccine effectiveness was 67.8% (95% confidence interval, 28.6% to 91.9%). After adjusting for confounders, vaccine effectiveness was 84.0%, but with a wide confidence interval (95% CI, –208.5 to 99.2).
The team concluded that the findings show moderate to high effectiveness of two doses, depending on the study design and analytical method. However, they said the trial's small sample size adds an element of uncertainty.
"This evidence supports the potential for a two-dose regimen to provide substantial protection in outbreak settings, which is crucial given the logistical challenges of administering a three-dose schedule during an outbreak," they wrote.