Paper on the risks posed by FMD carriers occurring amongst vaccinated cattle

The presence of FMD in many parts of the world implicates that veterinary authorities and stakeholders in Europe always will have to accept the risk of incursions of FMD. Although vaccination by itself does not produce carriers, vaccinated ruminants when exposed to FMD virus some can become carriers (vaccinated carriers). When discussing vaccination policies as a means of controlling FMD outbreaks, the perceived “carrier risk” appears to be the main argument against such policy. Historical evidence shows that healthy bulls occasionally transmitted FMD to susceptible livestock. However, so far such evidence does not exist for vaccinated carriers. Also, under a variety of experimental conditions, transmission of FMD from recovered as well as vaccinated carriers has not been demonstrated. Still, (according to the norms of the OIE Terrestrial Code) if vaccination is used to eradicate FMD it takes longer to obtain the FMD free status than after stamping-out. Is that policy justified? What is the level of risk of the presence of vaccinated carriers and how does it compare with other FMD risks that the European society and international trade organizations have been willing to take? The purpose of this discussion paper is: • to explore if a “benchmark“ for acceptable risk can be defined; • to explore the types and accepted levels of FMD risks Europe has been exposed to in the past; • to compare, those risks to the levels of risk posed by recovered and vaccinated virus carriers. We conclude that current policies for controlling outbreaks and the consequences for export trade as yet are not based on risk assessment but on a “zero risk” approach. Reconsideration of that approach is needed to give veterinary authorities and livestock industry the best and safest options for FMD control while enabling safe international trade.