However strong the vaccination, this level of infectivity could overcome immunity, at least in some animals. So if one or two pigs in a herd catch the disease, they might pass it to others, even if they have been vaccinated. Uruguay successfully tackled the disease by vaccinating cattle but not sheep. Different Approaches to Vaccination 12. Vaccination can be used in different ways.
People talk of ring vaccination, protective vaccination, suppressive vaccination etc.
Sometimes different people mean different things by the same term. The following paragraphs suggest one way to think about the different approaches. To be effective, the vaccination zone needs to start well away from the source of the infection, to avoid the risk that animals within it are already infected. Movements of susceptible animals and people who may have been in contact with them across the zone need to be carefully controlled for as long as the outbreak lasts, and for several weeks after the last outbreak in the infected area. In practice, however much care is taken, firebreak vaccination may not be completely effective in containing infection within an infected area, but, when it works well, the numbers of cases outbreaks occurring outside the zone are likely to be few, and therefore more easily controlled.