Vietnamese vaccine producer AVAC Vietnam has conducted a controlled challenge study to assess the cross-protective performance of its commercial ASF vaccine, Avac ASF Live, against emerging mixed ASF virus strains combining genotype I and II — variants increasingly detected in Vietnam since late 2023.
The trial, held in late December 2025 in coordination with Vietnam’s central veterinary diagnostic authorities and international research partners, tested vaccinated and unvaccinated pigs under both injection and oral exposure routes. Viral challenge doses ranged from 20 to 2000 HAD50, reflecting infection pressure closer to commercial farm conditions rather than extreme laboratory settings.
According to Avac, results indicate that while Avac ASF Live continues to provide strong protection against genotype II — the dominant strain in Vietnam since 2019 — protective efficacy declines under high-pressure challenge with genotype I/II mixed strains. The company acknowledged this limitation, noting that genetic diversification of ASF viruses is increasingly shaping vaccine performance outcomes.
Based on these findings, Avac is pursuing a two-track strategy: continued evaluation of field-level protection from the current commercial vaccine, alongside development of a next-generation ASF vaccine built on genotype I/II mixed strains, targeted for potential release in 2026.
The assessment also reinforces Avac’s view of ASF vaccination as a risk-reduction tool rather than a standalone disease elimination solution, aimed at lowering outbreak probability and limiting spread under real production conditions.
Avac ASF Live has been commercially licensed in Vietnam since July 2022 and has been exported to multiple markets, including the Philippines, Indonesia and Nigeria, with total overseas shipments approaching one million doses.
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