For some years now a debate has raged about the ideal frequency of vaccinations and even the need for them at all. On one side we have much of the UK veterinary profession which claims that annual boosters are essential, at the other extreme we have a handful of zealots who seek to show that all vaccinations are harmful. They question the effectiveness of human as well as pet vaccinations – I wonder how they explain the total disappearance of smallpox in one generation if the worldwide programme to eliminate it didn’t work! Clearly the vaccine manufacturers have a strong motive to recommend annual vaccinations. The same profit motive could also apply to the vets. However, no vaccine is 100% effective in every individual dog and if a vet recommended less than annual vaccination (thus going against the manufacturers’ recommendations) to a client whose dog subsequently died of, say, distemper, I can imagine the lawyers having a field day.
An expert in the field, Prof Schultz, (Department of Patho-biological Sciences, School of Veterinary Medicine, University of Wisconsin) says “It has been common practice since the development of canine vaccines in the late 1950's to administer them annually. The recommendation to vaccinate annually was based on the assumption that immunity would wane in some dogs, thus to ensure immunity in the population, all dogs required revaccination since it was not practical to test each animal for antibody. Little or no research has been done to demonstrate that the practice of annual revaccination has any scientific value in providing greater immunity than would be present if an animal was never revaccinated or was revaccinated at intervals longer than one year.” He goes on to explain that in a 1978 report, American Vets were recommended to give the primary vaccinations to puppies followed by a booster at one year and thereafter at intervals of three years. More recently it has been pointed out that there is no evidence to support the three year interval. Another leader in this field, Dr Jean Dodds says "all of the 27 veterinary schools in North America are in the process of changing their protocols for vaccinating dogs and cats….Dogs' and cats' immune systems mature fully at 6 months. If a modified live virus is given AFTER 6 months, it produces immunity which is good for the LIFE of the pet (ie distemper, parvo). If another MLV vaccine is given a year later, the antibodies from the first vaccine NEUTRALIZE the antigens of the second vaccine and there is little or no effect. Not only are annual boosters for parvo and distemper unnecessary, they subject the pet to potential risks of allergic reactions and immune-mediated hemolytic anemia.”
These comments apply to Parvovirus and Distemper but not to Leptospira. Until recently its vaccine has given about 6 month’s immunity only. This matters particularly because it can be passed on to humans as Weils Disease (“rat-bite fever”). This is fairly uncommon but not readily diagnosed and has a fatality rate in humans of about 50%. As it is spread by rodents, especially rats, getting rid of these pests is a good idea. There is no vaccine available for humans, but a new vaccine has been produced for dogs which is guaranteed to last for at least one year and may last two.
Where does this leave you and your dogs? For the last 7 years, for my own dogs I have done the puppy vaccinations followed by a booster at one year and nothing thereafter. However, now the new Leptospira vaccine is available I am considering giving that to the adults every two years – remembering the saying that you are never more than 8 feet from a rat!