Knowing how the virus changes during the first few weeks of infection provides important information about its adaptability. Researchers from the Department of Molecular and Medical Virology and the Department of Translational Computer Infection Research at Ruhr University Bochum in Germany took a closer look at the early stages of hepatitis E infection. To do this, they worked closely with the blood donation service of the NRW Heart and Diabetes Center in Bad Einhausen, a hospital of the Ruhr University Clinic Bochum. The research team analyzed samples taken from 80 blood donors who were found to be infected with HEV during routine testing. The results will be published in the journal mBio from July 10, 2026.
Rapid evolution despite low diversity
Otherwise healthy people usually do not notice acute hepatitis E infection. The immune system usually eliminates the virus within a few weeks. However, the infection can become chronic in people who have a weakened immune system or whose immune system is suppressed by drugs.
To better understand what changes occur during the first few weeks of infection, the research team focused specifically on this early stage.
The virus occurs during acute infection. We wanted to know how diverse virus populations are and what changes often occur during this period. ”
Saskia Janshoff, PhD student and lead author of the study
The analysis showed relatively low genetic viral diversity among blood donors compared to the chronic phase of infection. However, the researchers were able to identify specific changes that recurred in multiple donors.
Recurrent mutations in polymerase genes
For sequencing, the team focused specifically on viral polymerases. This enzyme is important for viral replication and is a target for antiviral drugs. The researchers discovered four sites in genetic material where similar changes occur particularly frequently.
The researchers examined the effects of these mutations in laboratory experiments. “We realized that some variants of the virus have almost no ability to self-replicate,” says Dr. Andre Gomer. Nevertheless, they can clearly exist within a mixed viral population. This is possible through a mechanism known in the art as trans-complementation. Defective virus mutants benefit from the simultaneous presence of an intact viral polymerase and are still able to replicate.
Dynamically changes within weeks
Additional insights were gained from different samples from individual blood donors that were tested repeatedly throughout the course of infection. Changes in the composition of viral populations in individual patients within weeks were observed. “The early stages of infection are very dynamic,” Gomer said. “Individual variants arise, change in frequency, or disappear. Such processes can only be visualized by repeatedly taking samples.”
Basis for further research
Why some mutations occur and remain transient despite limited replicability is still not fully explained. Researchers hypothesize that certain changes may affect interactions with the immune system. However, further research is needed to show whether this actually benefits the virus. This study thus provides new insights into the early evolution of hepatitis E virus and lays the foundation for future studies on the importance of genetic changes in disease course and response to treatment.
cooperation partner
The study involved researchers from Ruhr-University Bochum, Ruhr-University Bochum University Hospital, Bielefeld University, HepE-Hub, TWINCORE Hannover, Hannover Medical School and the German Center for Infectious Disease Research.
funding
This study was funded by the Federal Ministry for Research, Technology and Space (VirBio; 01KI2106; HepEDiaSeq 01EK2106A/B) and the German Center for Infectious Disease Research.
sauce:
Reference magazines:
Janshoff, S. others. (2026). Intrahost viral population dynamics during acute hepatitis E virus infection. mBio. DOI: 10.1128/Race.01151-26. https://journals.asm.org/doi/10.1128/mbio.01151-26
