In this article, we explore the science driving VAX4ASF’s mission to prevent African swine fever: from decoding the virus’s complexity to designing next-generation vaccines for a safer, more sustainable future.
African swine fever (ASF) is a highly contagious viral disease that affects both domestic pigs and wild boars, causing severe economic and social losses worldwide. Despite not posing a threat to human health, ASF has had a devastating impact on the pig industry and food security, with outbreaks leading to the death or culling of millions of animals. With no approved vaccine for the European Union, research efforts such as those carried out within the EU-funded VAX4ASF project are essential to develop new, effective, and safe tools for prevention and control.
A complex virus and a global challenge
The African swine fever virus is a large double-stranded DNA virus belonging to the Asfarviridae family. Its genome, encoding more than 150 genes, produces a wide range of proteins that enable the virus to evade the animal’s immune defences. In addition, the virus remains stable in the environment for long periods and can persist in contaminated meat, carcasses, and materials, making it particularly challenging to eliminate once introduced.
Transmission occurs through direct contact between infected and healthy pigs or indirectly via contaminated feed, equipment, clothing, vehicles, and certain tick species. These complex infection routes, combined with the virus’s genetic variability and environmental resilience, explain why African swine fever continues to spread across regions and continents, challenging existing biosecurity and control measures.
Understanding immunity to drive vaccine innovation
Developing a vaccine against African swine fever virus remains one of the greatest challenges in veterinary science. The virus’s complexity, its capacity to modulate the immune system, and the limited cross-protection between different genotypes have long hindered vaccine development. To overcome these obstacles, VAX4ASF is pursuing innovative research strategies that integrate virology, immunology, and biotechnology to advance the creation of a safe and effective vaccine.
The project focuses on producing replication-limited vaccine candidates, which are viruses genetically engineered to replicate only once and therefore cannot cause disease in animals. This approach ensures that they trigger a protective immune response while preventing the possibility of further replication or reversion to virulence. These candidates are being generated using innovative molecular approaches designed to restrict viral replication and ensure vaccine safety, supported by multidisciplinary research across virology, immunology, and biotechnology.
Understanding how the virus interacts with the pig’s immune system is essential to identify which viral components can trigger protection and which contribute to immune evasion
While the initial generation of replication-limited vaccine candidates takes place within dedicated laboratory work packages, their design is guided by fundamental research on virus genetics, pathogenicity, and host immune responses. Understanding how the African swine fever virus interacts with the pig’s immune system is essential to identify which viral components can trigger protection and which contribute to immune evasion. This knowledge helps scientists define the molecular basis of immunity and supports the rational design of vaccine prototypes with improved efficacy and safety.
Within this framework, VAX4ASF investigates the mechanisms of cross-protection and immune modulation, focusing on how different African swine fever virus genotypes influence immune recognition. By studying these virus–host interactions, researchers aim to pinpoint specific viral genes that can be targeted in vaccine formulations or used as markers for DIVA (Differentiating Infected from Vaccinated Animals) testing. The DIVA concept refers to diagnostic methods that make it possible to distinguish naturally infected animals from those that have been vaccinated. This fundamental work complements vaccine development activities, ensuring that each candidate is informed by the latest scientific insights into African swine fever virus biology and immunology.
Collaborative European research for global impact
VAX4ASF unites leading expertise across Europe and beyond to advance scientific understanding of African swine fever. The project applies a multidisciplinary approach that integrates virology, immunology, epidemiology, and biotechnology to develop innovative vaccine solutions and complementary diagnostic tools.
The project contributes to improving animal health, strengthening food security, and supporting the sustainability of the European bioeconomy
Beyond vaccine development, VAX4ASF investigates virus–host interactions, immune mechanisms, and epidemiological models to inform effective control strategies for both wild and domestic pig populations. These models help researchers understand how African swine fever spreads under different conditions and evaluate how vaccination could be most effectively applied in real-world settings to prevent and contain outbreaks. Through this One Health and science-based approach, the project contributes to improving animal health, strengthening food security, and supporting the sustainability of the European bioeconomy.
Preparing for long-term prevention
African swine fever remains a major threat to global livestock systems. By advancing innovative vaccine technologies and diagnostic tools, VAX4ASF represents a decisive step towards long-term prevention and disease preparedness. Through scientific excellence, collaboration, and stakeholder engagement, the project is paving the way for a safer, more resilient, and sustainable future for animal health in Europe and beyond.