In a press statement, the World Organization for Animal Health (WOAH) has warned pig industries worldwide to be cautious in using only high-quality vaccines against African Swine Fever (ASF) with proven efficacy and safety.

Furthermore, WOAH stated that vaccines should undergo regulatory assessments and approvals in accordance with WOAH's international standards.

Use of non-compliant ASF vaccines

WOAH wrote: "The use of non-compliant and poor-quality vaccines may not provide any protection against ASF and risks spreading vaccine viruses that could lead to acute or chronic diseases.

Moreover, these vaccine viruses could also recombine with field strains to generate new strains that could evade detection and lead to acute, chronic, and persistent ASF infections on farms."

The organization emphasizes that any vaccination effort should be part of a larger plan. "Regardless of vaccine effectiveness, vaccination programs should be implemented as part of a comprehensive prevention and control strategy, which should include other critical control measures such as strict biosecurity, import measures, and movement controls."

Well-designed vaccination program

"Vaccination, if used, should be carried out within a well-designed vaccination program, taking into consideration, among other factors, the local epidemiology of the disease, expected vaccination goals, and the adequacy and sustainability of relevant technical, financial, and human resources.

These should always include post-vaccination surveillance and monitoring, as well as an exit strategy for ceasing vaccination, as mentioned in WOAH's international standards on vaccination."

Vietnam has approved 3 ASF vaccines

As the first country in the world, Vietnam has committed to approving various ASF vaccines. At this time, the country has granted market authorization for vaccines from both AVAC and Navetco.

A third vaccine producer, Dabaco, has also announced its plan to develop a vaccine. AVAC has also entered the evaluation process in the Philippines.

The use of non-compliant vaccines has led to various undesirable side effects, for example, in China. One of the most unfortunate developments was that, in November 2021, genotype I of ASF appeared in the country, even as Eastern Europe, Asia, and the Caribbean were trying to combat outbreaks of genotype II.

The hypothesis was raised that the genotype had reached China "to be evaluated as potential candidates for the ASF vaccine in China."

Experts at that time were already saying that this development could complicate protection through a potential vaccine based on genotype II.

On the way to licensed ASF vaccines

Convinced of the added value that international recognition of high-quality vaccines would bring, WOAH is monitoring the progress of several candidates for ASF vaccines at different stages of development.

Some countries have either approved or are conducting field studies for the use of genetically modified live vaccine candidates against genotype II of ASF.

A new standard project for the production of safe and effective vaccines against ASF was proposed in the September 2023 report of the WOAH Biological Standards Commission. WOAH encourages vaccine producers and members to consider these standard projects when developing and evaluating ASF vaccine candidates for regulatory approval and to provide their comments.