Booster administration can make a difference in the antibody response to intradermal foot-and-mouth disease vaccination in cattle.

Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals. Routine vaccination is one of the preferred methods of protection against this disease in endemic countries. For protective immunity against FMD, repeated immunizations with frequent administration are required. Intradermal immunization has many advantages over intramuscular administration of vaccines. In this study, a commercial tetravalent FMD vaccine adjuvanted with Montanide ISA 206 was administered to cattle via the intramuscular (2 mL [n = 10] and 0.5 mL [n = 9]) and intradermal (0.5 mL [n = 11]) routes. Booster doses were administered 28 days later using the same vaccine and routes. Serum samples were collected on days 0, 7, 14, and 28 post-vaccination (pv) and at 30 and 60 days post-booster. Homologous and heterologous virus neutralization tests and liquid-phase blocking and isotype ELISAs were used to measure the antibody response. The results showed that intradermal administration of quarter doses of the vaccine provides an equal or better virus neutralization antibody response than intramuscular administration of the same dose of vaccine after booster administration in cattle. This means that four times more cattle can be immunized with the same amount of vaccine using the intradermal route without compromising immunity.