For a long time all new puppies and kittens were given a standard vaccination, which protected them from a number of infectious diseases. Recently a number of new vaccines have been developed and pet owners and veterinarians have begun to question the value of routine annual vaccination for adult pets.
This has led to development of the concept of tailored vaccination protocols. If your pet is not likely to be exposed to a disease there is little point in vaccinating them against it. Your vet will be able to advise you on the most appropriate choice of vaccine for your pet weighing up the benefits of protection against any risk associated with the vaccine.
An optimal vaccination programme:
- Maximises the number of animals within the population that receive vaccination
- Ensures that only animals that have a realistic risk of contracting disease are vaccinated
- Minimises the total number of vaccinations each animal receives in a lifetime.
There is minimal benefit to be derived from vaccinating an individual with an antigen for which likelihood of exposure is low and where clinical disease is, in any case, mild.
In almost all cases puppies should be vaccinated against the major infectious diseases: distemper, canine hepatitis, leptospirosis, parvovirus (and probably parainfluenza virus) (DHLPPi). Puppies presented before 8 weeks can be vaccinated with DHLPPi using some vaccine brands, this is advantageous to allow early socialisation. The initial vaccination course can be completed after 10 weeks of age.
There is continued debate about the appropriate intervals for booster vaccinations in order to maintain immunity against the full range of infectious diseases in all individuals. Revaccination is generally required at intervals of 1 to 3 years against most diseases (this varies depending on the brand, and the disease for which protection is required).
Vaccination to protect against Bordetella bronchiseptica (one of the causes of kennel cough) is usually only carried out in at risk individuals – often just prior to entry to boarding kennels. The immunity produced by this vaccine does not last long and revaccination is required as often as every 6 months to maintain protection.
Vaccination is an essential part of a healthcare programme for domestic pets. The ideal strategy maximises the beneficial effects of vaccination whilst minimising risks to the patient. This means ensuring that not only does each individual receive only the most appropriate vaccinations, but that these vaccines are effective.
The effectiveness of vaccines can be reduced by poor storage and inappropriate administration techniques but is also determined by the health of the animal being vaccinated. For this reason your vet will perform a full clinical examination before vaccinating your pet so that signs of disease are detected and appropriate action can be taken. Vaccination of an individual already incubating infectious disease is unlikely to be effective.
If your pet is suffering from another condition vaccination may be even more important. Animals with chronic, controlled diseases such as diabetes mellitus should receive regular vaccination. The ability of an animal to mount an adequate response to vaccination can also be affected by poor nutrition, concurrent drug therapy e.g. immunosuppressive drugs, and ‘stress’.
Remember that in any population; even with the strictest attention to correct administration, a small number of individuals may fail to respond to any vaccine.
An adverse event is defined as “any undesirable occurrence after the use of a vaccine – whether or not the product causes the event”. Reactions to vaccines can be divided into 3 groups:
- Acute: occurring within 24-72 hours of vaccination, e.g. swelling of the face.
- Medium-term: delayed immune response occurring 1-6 weeks after vaccination. These reactions may include suppression or stimulation of the immune response, e.g. development of joint stiffness or other diseases of the immune system.
- Chronic: often years after initial vaccination, e.g. injection site tumours in cats.
Some breeds of dog including Old English Sheepdogs, Springer Spaniels and Weimeraners, appear to be more likely to develop vaccination reactions. However, many of these breeds also have a naturally high incidence of diseases of the immune system.
Joint disease (polyarthritis) has been reported in young Weimeraners and some people associate this with vaccination but since this disease usually develops around 13 weeks of age and most puppies are vaccinated around 10 and 12 weeks it is easy to understand why there appears to be a link between vaccination and disease. There are just too few controlled studies (where some animals are not vaccinated) to draw meaningful conclusions.
When considering vaccination protocols it is very important to weigh up the risks of infectious disease against any potential problems caused by vaccine. You should remember that vaccinations are very safe and reactions are rare – talk to your vet if you are concerned about your pet.
There is some anecdotal evidence to support claims that some diseases of the immune system may be associated with vaccination. However, it should be remembered that these complications are extremely rare and the risk of serious illness (or death) is much higher from the infectious diseases that the vaccine are protecting against.
Studies from America now provide evidence of an association between the use of particular vaccines and the development of certain tumours at injection sites in cats. It has been reported that the risk of injection site sarcomas increases with the number of vaccinations. If you are concerned about this risk in your pet raise the subject with your own vet who will be happy to discuss the issues with you.
There is no doubt that vaccines have been the key factor in the control of serious infectious diseases and have played an important part in the improvement of canine health. The control of infectious disease in humans is a ‘population issue’ – the Government sets a target for vaccinations in children (over 90%), in order to achieve population immunity. The situation in veterinary medicine is different. Levels of vaccination are much lower – in many areas the percentage of pets that receive vaccination is around 50%.
Pet owners pay to have their pet protected by vaccination – not to protect the general dog and cat population. This means that vaccination policy for pets are based on the worst responders so that all vaccinated pets are continually protected. Vaccination of pets is therefore more akin to the vaccinations we have before travelling abroad to protect our families and ourselves.
Protection afforded by vaccination is not necessarily life-long. The duration of immunity varies depending on the circumstances of the individual animal and the vaccine used. Long-term protection afforded by vaccinations varies according to the manufacturer and the antigens contained. For example Leptospirosis vaccines provide adequate protection for less than a year in most animals.
The level of infection in the environment of many of the diseases against which we vaccinate (notably distemper and infectious hepatitis) is low. This means that it is unlikely that a vaccinated animal will come into contact with the wild strain virus sufficiently frequently to receive natural boosts to its immunity. Repeated vaccination is necessary to maintain adequate antibody titres in these cases.