Foot-and-Mouth Disease Virus: Immunobiology, Advances in Vaccines and Vaccination Strategies Addressing Vaccine Failures—An Indian Perspective

Abstract

A mass vaccination campaign in India seeks to control and eventually eradicate foot-and-mouth disease (FMD). Biosanitary measures along with FMD monitoring are being conducted along with vaccination. The implementation of the FMD control program has drastically reduced the incidence of FMD. However, cases are still reported, even in regions where vaccination is carried out regularly. Control of FMD outbreaks is difficult when the virus remains in circulation in the vaccinated population. Various FMD risk factors have been identified that are responsible for FMD in vaccinated areas. The factors are discussed along with strategies to address these challenges. The current chemically inactivated trivalent vaccine formulation containing strains of serotype O, A, and Asia 1 has limitations including thermolability and induction of only short-term immunity. Advantages and disadvantages of several new-generation alternate vaccine formulations are discussed. It is unfeasible to study every incidence of FMD in vaccinated animals/areas in such a big country as India with its huge livestock population. However, at the same time, it is absolutely necessary to identify the precise reason for vaccination failure. Failure to vaccinate is one reason for the occurrence of FMD in vaccinated areas. FMD epidemiology, emerging and re-emerging virus strains, and serological status over the past 10 years are discussed to understand the impact of vaccination and incidences of vaccination failure in India. Other factors that are important in vaccination failure that we discuss include disrupted herd immunity, health status of animals, FMD carrier status, and FMD prevalence in other species. Recommendations to boost the search of alternate vaccine formulation, strengthen the veterinary infrastructure, bolster the real-time monitoring of FMD, as well as a detailed investigation and documentation of every case of vaccination failure are provided with the goal of refining the control program.

High-Resolution Composition Analysis of an Inactivated Polyvalent Foot-and-Mouth Disease Vaccine

“…The seven serotypes (O, A, C, Asia 1, Southern African Territories 1, 2, and 3) cause indistinguishable disease but are antigenically distinct, with no cross-protection after infection or vaccination [2,12]. Even within a serotype, cross-protection between lineages is variable and the emergence of new variant viruses can lead to a reduced efficacy of existing vaccines [13][14][15]. This antigenic variation constitutes a major problem in the control of FMDV and has to be considered in vaccine development and application.…”

Meta-analysis of genetic diversity of the VP1 gene among the circulating O, A, and SAT2 serotypes and vaccine strains of FMD virus in Egypt

“…( 25 ) and Singh et al . ( 31 ). In our study, the combined assessment of the quantitative FMD data available in GenBank and WRL from several years provides a better view of the prevalence of the three serotypes.…”

“…Consequently, a different strategy is required for selection of the vaccine strain of the three circulating serotypes. Strategy formulation is a contributor to the difficulty of FMD outbreak control when the virus remains in circulation in the vaccinated population ( 31 ).…”

Promotion of Cellular and Humoral Immunity against Foot-and-Mouth Disease Virus by Immunization with Virus-Like Particles Encapsulated in Monophosphoryl Lipid A and Liposomes

“…FMD is one of the most economically devastating veterinary diseases worldwide [ 32 ]. Although a chemically inactivated whole FMD vaccine has been widely used and is known to provide a reduction in FMD prevalence in endemic areas, there is a clear need for a new generation of FMD vaccines to improve overall immunogenicity and safety [ 33 ]. Among the several types of vaccines employed for veterinary and human needs, VLP FMDV vaccines have been proven to show reliable immunogenicity and safety in pre-clinical and clinical studies [ 34 , 35 , 36 ].…”