Global Foot-and-Mouth Disease Research Update and Gap Analysis: 3 - Vaccines

Abstract

SummaryThis study assessed research knowledge gaps in the field of FMDV (foot-andmouth disease virus) vaccines. The study took the form of a literature review combined with research updates collected in 2014 from 33 institutes from across the world. Findings were used to identify priority areas for future FMD vaccine research. Vaccines play a vital role in FMD control, used both to limit the spread of the virus during epidemics in FMD-free countries and as the mainstay of disease management in endemic regions, particularly where sanitary controls are difficult to apply. Improvements in the performance or cost-effectiveness of FMD vaccines will allow more widespread and efficient disease control. FMD vaccines have changed little in recent decades, typically produced by inactivation of whole virus, the quantity and stability of the intact viral capsids in the final preparation being key for immunogenicity. However, these are exciting times and several promising novel FMD vaccine candidates have recently been developed. This includes the first FMD vaccine licensed for manufacture and use in the USA; this adenovirus-vectored FMD vaccine causes in vivo expression of viral capsids in vaccinated animals. Another promising vaccine candidate comprises stabilized empty FMDV capsids produced in vitro in a baculovirus expression system. Recombinant technologies are also being developed to improve otherwise conventionally produced inactivated vaccines, for example, by creating a chimeric vaccine virus to increase capsid stability and by inserting sequences into the vaccine virus for desired antigen expression. Other important areas of ongoing research include enhanced adjuvants, vaccine quality control procedures and predicting vaccine protection from immune correlates, thus reducing dependency on animal challenge studies. Globally, the degree of independent vaccine evaluation is highly variable, and this is essential for vaccine quality. Previously neglected, the importance of evaluating vaccination programme effectiveness and impact is increasingly being recognized.

A Single Dose of Dendrimer B2T Peptide Vaccine Partially Protects Pigs against Foot-and-Mouth Disease Virus Infection

“…In addition, the growing numbers of domestic pigs worldwide, particularly in Asian countries, make the development of pig-suited FMD vaccines a strategic task. Conventional FMDV vaccines based on chemically inactivated virus have allowed FMD control and eradication in some countries, although their manufacturing process-not upgraded over recent decades-poses significant biosafety concerns that have been related to occasional escape episodes of diverse consequence [12][13][14]. This risk plus other limitations, such as the need for a strict cold chain to preserve stability, and the use of updated vaccine strains, because of the high potential antigenic diversity of the virus, underlie the adoption of non-vaccination policies in FMDV-free countries, a controversial and by no means risk-free practice, as borne out by not infrequent outbreaks in those locations.…”

Emergency Foot-and-Mouth Disease Vaccines A Malaysia 97 and A22 Iraq 64 Offer Good Protection against Heterologous Challenge with A Variant Serotype A ASIA/G-IX/SEA-97 Lineage Virus

“…Due to its infectious nature and potential impact on trade, it is important to prevent the accidental introduction of the virus into a previously "FMD free" country. If an incursion occurs, vaccines can play a vital role in effective control of the disease, both to limit the spread of the virus during epidemics and the economic impact [1].…”

Molecular Mechanisms of Foot-and-Mouth Disease Virus Targeting the Host Antiviral Response

“…Disease control involves slaughter of infected and in-contact animals, restriction of animal movement, and vaccination based on chemically-inactivated virus (Robinson et al, 2016a). To develop new strategies for rapid FMDV control, including antiviral approaches and novel vaccines, it is essential to gain a better understanding of the virus-host interplay.…”