Vaccines

The idea of inoculations using a mild form of a disease to provide protection from more severe disease was pioneered in the late 18th century.  Edward Jenner conducted a series of experiments, concluding that the pus collected from a rash on his milkmaid’s hand was cowpox, a disease picked up from his milking cow, Blossom.  When the cowpox-infected pus was put into another person, it was protective against the closely related and much more severe human disease, smallpox.  In the late 19th century, Louis Pasteur coined the term ‘vaccine’ to cover all protective inoculations in honour of Jenner’s experiments a century earlier after the Latin for cow, vacca.  The 20th century saw the steady rise of safe, readily available and effective commercial vaccines, which revolutionised both human and veterinary medicine.  Significant improvements to animal welfare and productivity would not have been possible without vaccines.

Of course, disease prevention and treatment over the last two centuries cannot be encompassed without discussing antibiotics; historically, revolutionary ‘magic-bullet’ treatments for bacterial diseases.  The rise of antimicrobial resistance (AMR) in recent years however, has given a pause for thought of blanket treatments with antibiotics.  The World Health Organisation (WHO), the veterinary world health organisation (OIE) and individual governments around the world have made considerable efforts recently to reduce AMR by advising and promoting more responsible use of antibiotics.  As we embark on a journey where antibiotics will not always be the first port of call, vaccines are likely to play an ever increasing role in disease management.

Autogenous or Emergency Vaccines

Commercial vaccines are a cost effective way of improving productivity and reducing costs in any herd or flock.  But what happens when a commercial vaccine does not exist for a particular disease, or when a vaccine appears to not work?  There are many possible reasons for vaccine breakdown, including improper storage and/or administration of the vaccine or poor individual animal response due to heavy disease burden and/or poor nutrition.  Another reason for vaccine breakdown however, can be due to changes to the organisms causing disease.  For survival, bacteria and viruses are under constant pressure to adapt to their environment and these adaptions can result in changes to the disease-causing microbes that are different enough from the vaccine to reduce its effectiveness.  These are called different serotypes and diagnostic tests can be used to differentiate them.  When a new serotype, not already included in a commercial vaccine, is found in circulation on a farm, a vet can prescribe an autogenous vaccine to be made from the farm-specific serotype.

Autogenous vaccines, from the Latin auto (self) + genous (from), are also often referred to as ‘emergency vaccines’ because they can be produced relatively quickly.  They are bespoke vaccines made from the isolate recovered from a specific farm during a disease outbreak and are used only in that specific farm.  Emergency vaccines can be prescribed by a vet in cases where no UK-licensed commercial vaccine exists, the commercial vaccine has been proven ineffective (e.g., different serotypes involved) or the commercial vaccine is not licensed for use in certain groups of animals (e.g., pregnant) or species (e.g., exotics). 

Benefits of using emergency vaccines are similar to commercial vaccines and include, improved recovery time, reduced treatment costs, reduced pathogen excretion and reduced antibiotic usage.  Being a bespoke product, emergency vaccines may also be made to include more than one pathogen or serotype, thus reducing the overall cost of vaccination, whilst improving efficacy.  Some emergency vaccines, such as those for warts in cattle, are often used therapeutically once the animal already has the disease to encourage the warts to drop off quicker.  Emergency vaccines are also useful in complex disease scenarios such as campylobacteriosis (vibriosis), where treatment can be time consuming and expensive, and with good biosecurity, may help with control and prevention of campylobacteriosis.  Emergency vaccines are already made for several different diseases and as new ones emerge, they are regularly added to the manufacture schedule.

Summary

Just as bacteria and viruses have evolved over centuries, so too has the field of medicine.  Modern medicine has entered a new era where the world strives to curtail the rise of antimicrobial resistance by reducing antibiotic usage.  All vaccines will become an increasingly important tool in the disease management process, though as emergency vaccines can be produced safely, relatively quickly, and due to their bespoke nature, are often highly effective, they may become increasingly helpful in outbreak scenarios. 

NationWide Laboratories (NWL) has been licensed by the Veterinary Medicines Directorate (VMD) for the manufacture of emergency vaccines since 1986 and has full Good Manufacturing Practice (GMP) accreditation through the VMD.  Herd-specific emergency vaccines can be prescribed by your vet and manufactured at NWL in 5 to 10 weeks.  To meet license requirements, these vaccines can only be prescribed under the following conditions:  there is no UK-licensed commercial vaccine available for the disease outbreak, the serotypes involved in the disease outbreak are not included in the commercial vaccine or the disease is presented in a group/species of animals for which the commercial vaccine is not licensed or may have adverse effects.  Talk to your vet for more information about autogenous, or emergency vaccines.

By Olivia Anstaett BSc, MSc, PhD

The Scottish Farmer:

*This article contains sponsored content and does not necessarily represent the views of The Scottish Farmer.