Abstract
African swine fever (ASF) is one of the most devastating diseases affecting the global pig industry. Therefore, the development of safe and effective vaccines is crucial in combating the virus. The AVAC ASF LIVE vaccine, produced from an attenuated genotype II ASF virus (ASFV) strain with the deletion of six MGF genes and cultured in a Diep's macrophage (DMAC) cell line, has been officially licensed for use and commercialization in Vietnam. This study evaluated the safety and efficacy of the AVAC ASF LIVE vaccine. In the safety experiment, pigs received a dose equivalent to 100 times the protective dose. In the efficacy experiment, control pigs and one-dose vaccinated pigs were challenged with a highly virulent p72 genotype II ASFV on day 28 post-vaccination. The duration of protective immunity was assessed by challenging pigs at various time points, from 2 weeks up to 6 months post-vaccination. Results showed that pigs given the 100-fold protective dose remained healthy with no abnormal signs. Significantly, 60% of vaccinated pigs survived the challenge 14 days after vaccination, and the survival rates reached 100% when challenged at 28, 90, 120, and 150 days post-vaccination (dpv). The vaccine effectively induced robust immunity, leading to a reduction in viral shedding and the persistence of viral DNA in vaccinated animals. In conclusion, the AVAC ASF LIVE vaccine has demonstrated safety and high efficacy in protecting pigs from genotype II ASFV infection.