WOAH warns for the risk of sub-standard ASF vaccines

In addition, the WOAH said, the vaccines should have been subject to regulatory evaluation and approval in accordance with WOAH international standards.

Use of non-compliant ASF vaccines

The WOAH wrote: “The use of non-compliant and poor-quality vaccines may not confer any protection against ASF and risks spreading vaccine viruses that could result in acute or chronic disease. Additionally, these vaccine viruses could also recombine with field strains to generate novel strains that could evade detection and result in acute, chronic and persistent ASF infections on farms.”

The organisation stresses that any attempt should be part of a bigger plan. “Regardless of vaccine efficacy, vaccination programmes should be implemented as part of a comprehensive prevention and control strategy, which should include other important control measures such as strict biosecurity, import measures and movement controls.”

Well-designed vaccination programme

“Vaccination, if used, should be conducted under a well-designed vaccination programme that takes into account, among other factors, the local epidemiology of the disease, the expected objectives of vaccination and the adequacy and sustainability of the relevant technical, financial and human resources. They should always include post-vaccination surveillance and monitoring as well as an exit strategy for the cessation of vaccination, as mentioned in WOAH international standards on vaccination.”

Vietnam approved 3 ASF vaccines

As 1st country in the world, Vietnam embarked on the approval of various ASF vaccines. At the moment, the country gave marketing authorisation for vaccines of the companies AVAC as well as Navetco. A 3rd vaccine producer, Dabaco, also announced to have a vaccine developed. AVAC has also entered the evaluation process in the Philippines.

The use of bootleg vaccines has led to various unintended side effects in for instance China. One of the most unlucky developments was that in November 2021, genotype I of ASF also emerged in the country, even though Eastern Europe, Asia and the Caribbean at the moment are trying to fight outbreaks of genotype II. It was hypothesised that the genotype had ended up in China “to be evaluated as potential ASF vaccine candidates in China.”

Experts at the time already said that that development could complicate the protection by a potential vaccine based on genotype II.

On the way to licensed ASF vaccines

Convinced of the added value that the international recognition of high-quality vaccines would have, WOAH is monitoring the progress of several ASF vaccine candidates at various stages of development. Some countries have either approved or are conducting field trials for the use of modified live vaccine candidates against ASF genotype II.

A new draft standard for the production of safe and effective vaccines against ASF has been proposed in the September 2023 report of the WOAH Biological Standards Commission. WOAH urges vaccine manufacturers and members to consider these draft standards when developing and evaluating ASF vaccine candidates for regulatory approval and to provide their comments.