Hepatitis E virus (HEV) is a major cause of acute viral hepatitis and is particularly harmful in low-income countries where it can cause large epidemics with a disproportionate toll on pregnant women and their offspring. Improving sanitation and safe drinking water can be challenging in high-risk settings such as refugee camps, and available treatments like Ribavirin are contraindicated during pregnancy.
A three-dose schedule of the HEV 239 vaccine (Hecolin®) has shown promising results on both efficacy and safety in a large Chinese study. However, there are still doubts about how these results translate into different settings such as a low-income country with different populations and circulating HEV genotypes.
In a recently published paper by Øverbø, Aziz et.al , the authors investigated the safety and immunological response of a two-dose regimen with the HEV 239 vaccine in 100 healthy participants from rural Bangladesh. The study was randomized, double-blinded and used a commercially available hepatitis B vaccine as control.
The results of the study showed that adverse events to HEV 239 were comparable to the control vaccine, mild in severity and resolved within one to nine days. All participants in the study group seroconverted and achieved high levels of HEV IgG antibodies that remained positive for two years in all but one participant. This study is also the first to demonstrate that HEV 239 elicits a T-cell response in humans.
Based on these results the team concluded that two doses of the HEV 239 vaccine is likely to be safe and produces broad and likely functional immune responses against HEV that remain for at least two years. The study provides hope that a relatively quick vaccination regime of two doses administered within one month could help prevent serious HEV disease and limit HEV transmission in vulnerable populations.
This study is an important step towards making the HEV 239 vaccine available in low-income countries, but larger studies are needed confirm these results and study the effectiveness of HEV 239 in diverse settings and populations. The research team is currently conducting a large study in Bangladesh to further investigate these findings and pave the way for making the HEV 239 vaccine available in low-income countries.
Read the full article (Vaccine. 2023 Jan 2;S0264-410X(22)01599-7): DOI: 10.1016/j.vaccine.2022.12.064
