WHO stresses the importance of using high-quality vaccines that meet the new standard

The ongoing spread of African swine fever ( ASF ) is causing concern for the global pig industry, as no region has escaped its impact. For many years, the lack of an effective vaccine or treatment has made disease control extremely difficult. The scientific community is working to develop an effective vaccine, and recent announcements of the approval or testing of modified live vaccines in several countries have raised hopes for effective new tools to contain the current ASF epidemic. Many countries are interested in using these vaccines as an additional tool to prevent and control the risk of ASF spreading within their territories. 

First adoption of standards for ASF vaccines 

The first standards for the production of safe and effective ASF vaccines were adopted in May 2025 by the OMSA Global Assembly of Delegates. OMSA urges vaccine manufacturers and its members to consider these standards when developing and evaluating candidate vaccines for regulatory approval. 

OMSA emphasizes the importance of using only high-quality ASF vaccines that meet the standards outlined in the Terrestrial Manual, have proven efficacy and safety, and have been evaluated and approved by the relevant national regulatory authority. 

Vaccination against ASF should not be used as the only control measure.

Regardless of vaccine effectiveness, vaccination programs should be implemented as part of a comprehensive prevention and control strategy, including other important measures such as surveillance for early detection, strict biosecurity, import measures, and movement controls. 

Vaccination, if used, should be conducted within a well-structured program that takes into account, among other factors, the local epidemiology of the disease, the expected vaccination objectives, and the adequacy and sustainability of available technical, financial, and human resources. These programs should always include post-vaccination surveillance and monitoring, as well as an exit strategy for discontinuing vaccination, as established by the WHO International Standards on Vaccination. 

Risks of using substandard or inadequate vaccines

The use of inappropriate or substandard vaccines may provide no protection against ASF and carries the risk of spreading vaccine viruses that can cause acute or chronic disease. Furthermore, these vaccine viruses can recombine with strains present in the field, creating new variants that can evade detection and cause acute, chronic, or persistent infections. 

WHO encourages its Member States to actively report incidents involving substandard vaccines that do not meet quality specifications after regulatory approval, in accordance with the sixth recommendation of Resolution 29, adopted in May 2025 by the WHO World Assembly of Delegates. These incidents can be reported through the WHO Global Alert System for Substandard or Falsified Veterinary Products (VSAFE pilot system) to strengthen vaccine quality surveillance and support their recall from the market.