Currently there is no commercialized vaccine for African swine fever (ASF). One of the most promising candidates to date is the highly effective and safe live attenuated vaccine candidate ASFV-G-ΔI177L, which is a recombinant virus that lacks the I177L gene. This candidate vaccine currently requires that the vaccine be kept frozen, which adds complexity to deliver the vaccine to areas that may not have the required freezing capabilities, such as rural areas in Africa or Asia, where ASF currently is causing outbreaks. A vaccine is an essential part of any eradication program. To overcome the limitation of cold storage, here we tested the ability of Lyophilization or freeze drying the vaccine, and the stability of the vaccine being stored at ambient or refrigeration temperatures. By using different combinations of stabilizing formulations, we have shown stability of a lyophilized version of ASFV-G-ΔI177L for up to two months. This is a major milestone in overcoming the required frozen storage of the ASFV-G-ΔI177L candidate vaccine.

Key Findings:

  • Stabilizing buffers allow for the stable lyophilization of ASFV-G-ΔI177L
  • Lyophilization of ASFV vaccines will help enable vaccination in rural areas where ASFV outbreaks are currently occurring
  • Optimizing Stabilizing buffers increased stability of the vaccine from days to months at refrigeration or room temperature