African swine fever (ASF) is a tricky disease to immunize ag­ainst, noted experts during last week’s World Pork Expo at the Iowa State Fairgrounds in Des Moines.

“Based on what we’re seeing right now, we’re unlikely to produce a sterilizing immunity by vaccine,” said Mike Roof, chief technology officer of the Vaccines and Immunotherapeutic Research and Innovation Platform at Iowa State University (ISU). “We now see an ASF vaccine as part of the solution.”

Iowa Secretary of Agriculture...