12 April 2000
Regular boosters still the best way for animal health
The summary heprepared for the meeting is enclosed.
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Notesfor editors
1.For futher information contact David Sutton on 01908665050, or Alison Glennon/Roger Cook at NOAH on 020 8367 3131. Or look on theNOAH website www.noah.co.uk
Qualified (RVC) in 1982.
Initially spent some time inmixed general practice in Norfolk.
Joined Mycofarm as UK VeterinaryAdviser.
Became part of the IntervetVeterinary Services team when Intervet acquired Mycofarm in 1988.
Currently employed as Head ofIntervet's UK Veterinary Services Department.
For many years now has been particularlyinvolved with the development and user support of Intervet's small animalvaccine range.
Currently chairman of:
NOAH Companion Animal Vaccine Group
NOAH Pharmacovigilance Working Group
FEDESA (European Industry) Pharmacovigilance WorkingGroup
3. The National Office of AnimalHealth was formed on 1 January 1986 to represent the UK companies whichresearch, develop, manufacture and market licensed animal health products. Theassociation has 35 corporate members and 12 associate members. In 1999 NOAH'smembers accounted for around 95% of the 371 million UK animal health market,with additional valuable exports.
4. The other speakers at theVaccination Colloquium, which took place at 2.00pm on 9 April, were R Ford(USA) and R Gaskell (UK).
Underpinning the above question are two key concerns:
1. Do we need to re-vaccinate every one or two years toprevent disease?
2. Does vaccination result in significant side effects to theextent that we are doing more harm than good?
Both of these concerns have been raised with increasingfrequency over the last few years and the debate has even moved from thescientific and specialist press to the mass media!
As manufacturers we are ultimately responsible for providingvaccines which are of inherent good quality and have been tested to prove thatthey are as safe and effective as claimed when used according to data sheetrecommendations.
In the licensing of our vaccines we have to assess efficacy:
using minimal titre product
in animals with no natural 'field' exposure toinfection, and thus no possibility of natural boosting of immunity
by challenging optimally healthy animals at intervalsgreater than the maximum booster interval with enough infectious load to causesevere (and probably fatal) disease in similarly fit & healthy unvaccinated(control) animals.
Thus we are ensuring as far as possible that the vaccinealone, under 'worst case' conditions, will protect for at least the claimedbooster interval.
Logic, and a knowledge of biological variation thus suggeststhat we are probably 'over vaccinating' many of our patients. Unfortunately there is as yet no cheap,simple & reliable method of assessing the degree of protection against allof the diseases we currently vaccinate against. Routine booster vaccination therefore remains the mostcost-effective way of ensuring protection, and is especially important in petswhich are unlikely to receive any natural boost from field infection and inthose which respond relatively poorly or where immunity has decayed morerapidly than the norm.
If we choose to extend these booster intervals, we may thusbe relying increasingly on 'herd immunity' and reduced population disease prevalencein order to avoid disease in individuals whose own vaccine-stimulated immunityhas 'run out of steam'.
The main driver for change over the last years has been anincreasing concern about the risk of side effects set against the background ofa perceived greatly reduced incidence of disease. The perception in many peoples' minds is that the safety risk ofrepeated vaccination now significantly outweighs the benefits! Although most of the practitioners I talk towould argue strongly against this proposition, based on their own clinicalestimates of the level of vaccine side effects and local incidence of disease,we are unfortunately not (yet) in a position to prove this based on formalepidemiological evidence. We do nothave the necessary data to be able to accurately quantify the level ofrecognised side effects following vaccination, nor in many cases do we knowwhether vaccination really does lead to an increased risk of e.g. variousauto-immune disorders - especially since we need to base our conclusions on thecurrent UK situation, using the vaccines and protocols advised in thiscountry.
Ultimately, we need further UK-based information, and inthis context, further studies and investigations are either underway or beingplanned. We would be well advised toawait the results of these before passing judgement on the vaccine risk/benefitequation, since, quite apart from the general concern as to the effects anywholesale reduction in the level of vaccination might have on populationimmunity, there are obvious questions of individual liability if problems arisewhere the practitioner is acting outwith data sheet recommendations.
In the meantime, on the basis of the best availableinformation, we can all provide sensible veterinary input to help add somebalance to much of the increasingly distorted 'anti-vaccine' propaganda ourbreeder and pet owner clients are being exposed to nowadays, in particular weshould be more proactive in:
explaining the benefits of vaccination
explaining that the risks of disease are nowadays lessthan they were many years ago (as a result of widespread vaccination!)
explaining that vaccination should be regarded as asensible 'insurance policy' which will significantly reduce the risks to thepet if he or she is exposed to infection
explaining that the annual 'vaccination' is actuallymuch more than that - it is a full consultation & health check, and hencethe fee is not just for the vaccine itself
actively reassuring any clients worried about vaccinesafety, based on what we know from existing UK information, including publisheddata from the UK Suspected Adverse Reaction Reporting Scheme, and - veryimportantly- from our own knowledge and experience as veterinary clinicians
working together as practitioners, academics andassociation & industry representatives in order to ensure that ourdecision-making is transparent and is based on all the relevant data.
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