Safety of ASFV vaccine candidate assessed

The U.S. Department of Agriculture’s Agricultural Research Service (ARS) has announced that a vaccine candidate for African Swine Fever (ASF) has passed an important safety test required for regulatory approval.

The test is an important milestone as part of a series of safety studies. These new results, published in Viruses, show that USDA’s live attenuated vaccine candidate does not revert to its normal virulence, after being injected into pigs. This “reversion to virulence” test is required to ensure that the vaccine’s weakened form of the ASF virus does not revert to its original state.

“This is a critical milestone for the ASF vaccine candidate. These safety studies bring this vaccine one step closer to being available on the market,” said senior ARS scientist Manuel Borca.

“It is very hard to predict how selective pressure can cause a live attenuated vaccine to return to virulence,” said senior ARS scientist Douglas Gladue. “In the case of this particular vaccine candidate, ASFV-G-DI177L, we deleted a gene, which makes it difficult for the virus to simply add the gene back. So, we expected reversion to its original form to be unlikely, but the test still has to be performed.”

The vaccine candidate was recently selected by NAVETCO for commercial development in Vietnam. NAVETCO has partnered with ARS on ASF vaccine research and development since 2020.

These safety studies are necessary to gain approval for use in Vietnam and eventually in other countries around the world. Future commercial use, however, will depend on approval from the department of animal health within each requesting country.

Article: Tran, X. H., Phuong, L. T. T., Huy, N. Q., Thuy, D. T., Nguyen, V. D., Quang, P. H., Ngôn, Q. V., Rai, A., Gay, C. G., Gladue, D. P., Borca, M. V. (2022). Evaluation of the safety profile of the ASFV vaccine candidate ASFV-G-ΔI177L. Viruses, 14(5):896, doi: 10.3390/v14050896