Requirements for improved vaccines against foot-and-mouth disease epidemics

Abstract

Inactivated foot-and-mouth disease (FMD) vaccines are currently used worldwide. With the emergence of various FMD virus serotypes and subtypes, vaccines must become more suitable for field-based uses under the current circumstances in terms of the fast and proper selection of vaccine strains, an extended vaccine development period for new viruses, protecting against the risk of virus leakage during vaccine manufacture, counteracting the delayed onset of immune response, counteracting shorter durations of immunity, and the accurate serological differentiation of infected and vaccinated animals and multiple vaccination. The quality of vaccines should then be improved to effectively control FMD outbreaks and minimize the problems that can arise among livestock after vaccinations. Vaccine improvement should be based on using attenuated virus strains with high levels of safety. Moreover, when vaccines are urgently required for newly spread field strains, the seed viruses for new vaccines should be developed for only a short period. Improved vaccines should offer superior immunization to all susceptible animals including cattle and swine. In addition, they should have highly protective effects without persistent infection. In this way, if vaccines are developed using new methods such as reverse genetics or vector vaccine technology, in which live viruses can be easily made by replacing specific protective antigens, even a single vaccination is likely to generate highly protective effects with an extended duration of immunity, and the safety and stability of the vaccines will be assured. We therefore reviewed the current FMD vaccines and their adjuvants, and evaluated if they provide superior immunization to all susceptible animals including cattle and swine.

Genetic and immunologic relationships between vaccine and field strains for vaccine selection of type A foot-and-mouth disease virus circulating in East Asia

“…Among these vaccine strains, A22 Iraq is reserved as a high-priority strain [18], while A Iran-05 is a recently added strain in the antigen bank [8]. The A Malaysia 97 strain protects against viruses prevailing in Southeast and East Asia [19] and is a widely used vaccine strain in many regions, including Korea [20].…”

Effects of Germanium Biotite Supplement on Immune Responses of Vaccinated Mini-pigs to Foot-and-Mouth Disease Virus Challenge

“…Several studies have reported that multivalent vaccines could provide clinical protection against FMD and mitigate large FMD outbreaks (Cox & Barnett, 2009;Elnekave et al, 2013;Park, 2013;Park et al, 2013). Despite the reported high efficacy of multivalent vaccines, the trivalent vaccine used in South Korea showed a low rate of antibody formation (60-80%) in the pig industry in South Korea from July 2011 to June 2012, according to type O ELISA assay (Park, 2013). Furthermore, there is considerable concern about the ability of trivalent vaccines to protect against the Andong strain, which is responsible for recent outbreaks in South Korea .…”

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“…With the emergence of various FMD virus serotypes and subtypes, vaccines must become more suitable for field-based uses under the current circumstances in terms of the fast and proper selection of vaccine strains and vaccine improvement should be based on using attenuated virus strains with high levels of safety through adoptation of the virus in the cell line [8].…”