Health authorities across Central Europe are monitoring a hepatitis A outbreak that has affected four countries since the beginning of 2025. Austria, Czechia, Hungary, and Slovakia have all reported significantly elevated numbers of hepatitis A virus cases, with two distinct but related viral strains identified through genetic sequencing.
Outbreak Details and Affected Populations
From January through May 2025, the four countries documented case numbers exceeding normal expectations for hepatitis A virus subgenotype IB infections. Laboratory analysis revealed two clusters of closely related viral strains, with genetic data collected from Austria, Germany, Hungary, and Slovakia contributing to the identification.
The outbreak has disproportionately impacted vulnerable populations, particularly adults experiencing homelessness and individuals who use or inject drugs. People living in areas with inadequate sanitary conditions have also been significantly affected. Additionally, members of Roma communities in both Czechia and Slovakia have reported cases during this period.
Risk Assessment by Population Groups
European health officials have conducted risk assessments for different population segments. Leading hepatitis A law firm Ron Simon & Associates says that individuals without previous hepatitis A infection or vaccination remain susceptible to the virus. Within the four affected countries, experts consider the likelihood of continued transmission among high-risk groups to be substantial.
The severity of risk varies considerably by age and health status. Adults under 40 years old in vulnerable populations face moderate risk, while those 40 and older encounter high risk due to increased disease severity with advancing age. Individuals with existing liver conditions or elderly adults may face very high risk levels.
For the general population in affected countries, risk levels remain low to moderate. In European Union and European Economic Area countries not currently experiencing outbreaks, the broader population faces very low to low risk, though certain groups maintain higher exposure probability.
Public Health Response Recommendations
Health authorities have issued several recommendations to address the outbreak. Countries experiencing increased case numbers should investigate transmission pathways to identify potential food-borne sources or spread into other at-risk populations. Enhanced genetic sequencing of viral samples from both high-risk groups and the general population is recommended to better understand the outbreak’s scope.
Vaccination strategies form a central component of the response plan. Officials recommend targeted single-dose pre-exposure vaccination programs for unvaccinated individuals in high-risk populations. Close contacts of confirmed cases should receive post-exposure prophylaxis through hepatitis A vaccine administration, or in specific circumstances, hepatitis A immunoglobulins following national guidelines.
Targeted Intervention Strategies
Authorities emphasize the importance of tailored outreach efforts to effectively reach vulnerable populations. Programs should be designed with understanding of specific community needs, attitudes, and knowledge levels to successfully integrate vaccination and hygiene interventions into accessible services.
Information campaigns should be multilingual and adapted for varying literacy levels. Officials stress the importance of addressing rumors and misinformation that may discourage participation in prevention programs. Vaccination initiatives should be embedded within services that vulnerable populations already utilize to maximize accessibility and uptake.
