Two good papers in the last few weeks, both in Vaccine.
1. Barnett et al (2004) 22: 1221-1232 Evidence that high potency foot-and-mouth disease vaccine inhibits local virus replication and prevents the 'carrier' state in sheep.
Single administration followed by aerosol challenge 14 days later. "Unvaccinated sheep showed signs of clinical FMD, whereas all the vaccinated sheep, regardless of antigen payload, were protected against clinical disease and development of viraemia."2. Eble et al (2004) 22: 1372-1378 Vaccination of pigs two weeks before infection significantly reduces transmission of foot- and-mouth disease virus.
"No virus transmission was observed in the -14dpi group, whereas virus transmission was observed in all contact pigs affecting both the non-vaccinated and the -7dpi group. The reproduction ratio R in the -14dpi vaccinated group was significantly lower than that of the non-vaccinated group. This study confirms the potential of vaccination as an important tool to reduce transmission of FMDV."So, in summary - given an interval of 14 days following vaccination - complete protection in sheep and no virus transmission in pigs. Seems very straight forward!
NB -7dpi = 7 days before inoculation
-14dpi = 14 days before inoculation