Peer reviewed study presented at Congress shows routine vaccines do not increase frequency of illness.

An independent and scientifically peer reviewed study presented in the UK for the first time at the 2004 BSAVA Congress in Birmingham has produced the clearest evidence yet that routine vaccination of dogs in the UK does not increase frequency of illness.The study - nicknamed POOCH (Practice Overview of Canine Health) - was carried out by the world renowned Animal Health Trust at Newmarket.

"This is completely contrary to the claims which have hit the headlines," says Dr James Wood, head of epidemiology at the Animal Health Trust. "People should understand that our research results clearly demonstrate the absence of any deleterious association between routine vaccination and signs of ill health."

The AHT's research took the form of an epidemiological investigation to evaluate the evidence for any temporal association between vaccination and ill-health in dogs. In total, more than 9,000 postal questionnaires were sent to the owners of a randomly selected population of dogs and just over 4,000 of these were returned and analysed. No temporal association was found between vaccination and ill-health in dogs after adjusting for potential confounders, such as age.

The study population consisted of dogs that had used the services of a veterinary practice within the previous 12 months. The British veterinary practices contacted were randomly selected from a national list. Dogs were then randomly selected from the computer databases of the 28 practices that agreed to participate. On receipt of the owners' completed questionnaires, details of the dogs' vaccination history were confirmed with the veterinary practice.

The survey found that older dogs in general exhibit more signs of illness, including chronic lameness, stiffness and bad breath, and that frequency of these signs increases continuously with age. However, the results demonstrated that recent vaccination (within a period of 3 months) did not increase the signs of ill-health by more than 0.5 per cent and could well actually decrease them by almost 5 per cent.

Of the 3,966 dogs assessed by the survey, 50.5 per cent were male. Ages ranged from two weeks to 23 years (median 6 years 4 months). The demographic data for 667 non-responder dogs was similar: 57 per cent were male, with an age range of three weeks to 20 years (median 6 years 3 months). There were 124 breed groups represented including 1076 crossbred, 348 Labrador Retrievers, 180 Jack Russell Terriers and 169 Border Collies.

Time since last vaccination ranged from one day to 17 years (median 6 months). 23 per cent of dogs were recently vaccinated (<3mo), 1 per cent (42) were unvaccinated and 1 per cent (42) had their vaccination status recorded as unknown. The dogs' vaccinations were predominantly combined boosters, including components to protect against distemper virus, para-influenza virus, canine parvovirus, Leptospira interrogans (serovars canicola and icterohaemorrhagica) and infectious hepatitis. Vaccinations against Bordetella bronchiseptica or against rabies had also been administered to some dogs. The POOCH survey is to be published in a forthcoming edition of the peer-reviewed scientific journal "Vaccine".

"Vaccination and ill health in dogs: A lack of temporal association and evidence of equivalence", D.S. Edwards, W.E. Henley, E.R. Ely, J.L.N. Wood, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK, CB8 7UU

The Animal Health Trust is a registered charity committed to improving the prevention, diagnosis and treatment of injuries and diseases which affect companion animals. Based in Newmarket, Suffolk, the Trust was established in 1942 and currently employs more than 200 scientists, veterinary surgeons and support workers.

The National Office of Animal Health was formed on 1st January 1986 to represent the UK companies which research, develop, manufacture and market licensed animal health products. The association now has 33 corporate members and 14 associate members. In 2002, NOAH's members accounted for well over 90 per cent of the £389 million UK animal health market.

The study was funded by members of the National Office of Animal Health (NOAH), the trade association for the manufacturers of licensed animal medicines, to properly investigate the safety of routine vaccination in the UK canine population.

NOAH submitted a proposal for a scientifically valid study, but AHT stressed that they were prepared to undertake the project only on the clear contractual understanding that the work would be completely independent and that NOAH could not influence either the outcome or the eventual publication of the results.