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. Meanwhile, action against the disease would need to continue within the infected area at the centre of the firebreak.
Suppressive vaccination aims to control the spread of infection within and out of an infected area.
It reduces the amount of virus circulating in the area, as the vaccinated animals will be less infectious. An approach along these lines has been agreed by the European Commission for use in the Netherlands. In the Dutch outbreak the EC approved vaccination of animals within 2 km of the infected premises, on condition that there was intensive surveillance for FMD within a further 10 km radius and that all vaccinated animals were eventually destroyed. Protective vaccination refers to vaccination of particular groups or species in an infected area in order to protect them against the spread of infection. It assumes that action continues in parallel to eradicate the epidemic in other groups or species.