Marshall Lightowlers (The University of Melbourne) and colleagues developed just such a vaccine, after more then ten years hard work. It is reasonably cheap, and works well. At least in the lab. Emmanuel Assana and colleagues from Antwerp and Cameroon now could prove that it does so in realistic circumstances, too.
They vaccinated 120 piglets at two, three and six months, and gave them a deworming medicine at three months, to make sure they did not carry an infection from before the vaccination. Each piglet, together with an untreated control animal, was handed out to a family, which let it roam free around the village, as is customary.
After a year not one vaccinated pig was infected, while twenty percent of control animals was.