Intradermal Vaccination with 1/10 Dose against Fmdv Protects Pigs as Well against Clinical Disease and Subclinical Virus Shedding as Intramuscolar Vaccination with a Full Dose

The aim of this study was to investigate whether intradermal (ID) vaccination against foot-andmouth disease (FMD) is suitable as an alternative for the usually used intramuscular (IM) route. We used vaccines containing a normal or 10-fold dose antigen and compared groups of pigs that were vaccinated ID with either 0.2ml or 4x0.2ml with groups of pigs that were vaccinated IM with a standard 2ml, 0.2ml or 4x0.2ml dose. As compared with the 2ml IM vaccinated pigs, the pigs vaccinated ID with 0.2ml of the same vaccine were equally protected against clinical disease and subclinical virus shedding. Moreover, although VN-titres at 28 days post vaccination (dpv) of the 0.2ml ID vaccinated group were lower as compared to the IM vaccinated 2ml group, logistic regression analysis of the virus neutralising antibody (VN) titres at 28 dpv, the number of virus shedding pigs and application method showed that the ID vaccinated pigs needed significantly lower VN-titres as compared to the IM vaccinated pigs in order to be protected against virus shedding. We conclude that the ID route might be used as an alternative for IM application of FMD vaccine. ID application might induce more efficient immunity against FMD and, moreover, because the dose required in the ID route is lower compared to the IM route, ID application may reduce the cost of FMD vaccination markedly.