The test is an essential milestone in a series of safety studies. These new results show that USDA’s vaccine candidate does not revert to its average virulence after being injected into swine. 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.
These safety studies are necessary to gain approval for use in Vietnam and eventually in other countries worldwide. However, future commercial use will depend on support from the animal health department within each requesting country.
Although the virus is causing profound economic losses to the swine industry, there have not been any outbreaks in the United States. The highly contagious ASF virus spread from Africa to the Republic of Georgia in 2007 and has since swept through Central Europe and Asia before reaching the Dominican Republic in 2021. The virus is unable to transmit from pigs to humans.
“It is tough 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, making it difficult for the virus to add the gene simply. So, we expected reversion to its original form to be unlikely, but the test still has to be performed.”
Click here to see more...