🧬 ASF Vaccine Breakthrough Highlights Progress—and Gaps—in Cross-Protection

Swine Web Research Insight | June 2025

A new study from the Pirbright Institute has delivered promising results for a live attenuated genotype II African Swine Fever (ASF) vaccine, showing it can protect pigs from genotype I—but not genotype IX—highlighting the complex path forward in global ASF control.

Published in Emerging Microbes & Infections (DOI link), this peer-reviewed research signals a step forward in the development of strain-specific ASF vaccines, while reinforcing industry concerns about cross-genotype protection, safety, and viral evolution.

🔍 What the Study Found

• The gene-modified vaccine, based on genotype II ASFV, successfully protected pigs from genotype I, which is prevalent in parts of Africa and has lower virulence.

• However, no protection was observed against genotype IX, a strain also circulating in East Africa.

• Researchers deleted the EP402R/CD2v gene, known to facilitate viral spread and persistence.

• The vaccinated pigs survived challenge infections with genotype I, while control animals did not.

⚠️ Reinforcing Industry Concerns

Swine Web has previously covered rising concern around recombinant genotype I/II ASF strains found in China, Vietnam, and Russia—posing a significant threat to vaccine efficacy.

• A March 2025 feature highlighted the risks of vaccine failure against recombinant strains, particularly as these hybrids gain ground in Asia.

• A Vietnamese report detailed reproductive failure linked to a genotype II vaccine-like strain with multiple gene deletions—raising field safety red flags.

The Pirbright data affirms one key message: genotype II-based vaccines are a vital tool, but not a universal solution.

🐖 What This Means for the Industry

African Swine Fever has reshaped global pork production. While China and parts of Asia are still recovering from widespread outbreaks, North America remains on high alert. Biosecurity remains essential, but an effective vaccine could alter trade flows, animal movement policies, and emergency planning.

This study:

• Validates genotype-targeted vaccine strategies for controlled, region-specific protection

• Signals the need for multi-genotype or broad-spectrum vaccine development

• Adds urgency to the creation of DIVA-compatible vaccines to protect both herds and trade integrity

🧬 What’s Next?

Pirbright researchers are working on:

• Expanding genotype coverage across emerging ASF strains

• Monitoring long-term safety and immunogenicity

• Developing DIVA-compatible platforms for real-world application

Meanwhile, industry leaders must stay informed, as ASF continues to evolve—not only biologically but politically and economically.

📚 Full Paper:
Gene‑modified genotype II live attenuated African swine fever virus induces cross‑protection against genotype I but not against genotype IX
Published: May 20, 2025 | DOI: 10.1080/22221751.2025.2505645

🧠 Swine Web Takeaway:
This breakthrough offers hope—but ASF is still steps ahead. Genotype specificity, recombinant evolution, and vaccine safety remain top challenges in the global push to control one of the most devastating diseases in swine history.