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My Puppy Needs Vaccinating - What Do I Do?

Although puppies are vaccinated routinely to provide protection against the major infectious diseases (Parvovirus, Infectious Canine Hepatitis, Canine Distemper Virus and Leptospirosis), it is important to be aware that inoculations are not completely risk free.

Vaccine Adverse Reactions - AAHA

While many puppies appear to tolerate the administration of vaccines well, a wide range of serious and sometimes fatal reactions have been reported to the Veterinary Medicines Directorate over the years.

Given the potential harm that vaccines can cause, what then is the safest way for a puppy to be vaccinated?

In a nutshell, the younger a puppy is when a vaccine is given, the greater the risk that the immature immune system will be disrupted in some way, or the body’s natural defences overwhelmed, with problems developing as a result.

Conversely, the older a puppy gets, the better developed the immune system becomes, and the more able it is to cope successfully with inoculations. 

Timing therefore, is key to minimising unwanted side-effects.

4 month of age - a turning point

Puppies with high levels of antibodies from Mum, can be immune to infection until 12 - 18 weeks of age. And so a vaccine given any sooner than this, is likely to be neutralized to a greater or lesser degree, resulting in a weakened immune response.

After 16 weeks of age, levels of maternal antibodies in most puppies are low or non-existent, which means inoculation is far more likely to result in a strong immune response and protective levels of antibodies.  

Waiting until this age to vaccinate however, may result in a period where a puppy is vulnerable to infection. And so if this route is taken, a pet needs to be confined to safe areas only, such as the garden or rural locations unfrequented by other dogs.


Before 10 weeks of age:

  • immunity provided by maternal antibodies means that inoculations given at this time are unlikely to protect a puppy against the core infectious diseases. This is why is vaccine manufacturers advise that they be repeated when puppies are older
  • the risk of immune system disruption is at its peak

After 10 weeks:

  • a single inoculation may result in sufficient immunity, but where maternal antibodies are high enough to interfere with the vaccine given, this may not be the case
  • the risk of the immune system derangement is lower, but still present   

After 16 weeks:

  • a single inoculation is most likely to provide protection against the 3 core infectious diseases, as in most puppies maternal antibodies will no longer be present
  • the immune system is better able to cope with vaccination at this age (although adverse reactions can still occur)

Confirming Immunity 

A simple blood test called VacciCheck is available, which can determine if a dog has protective level of antibodies present against Parvovirus (CPV), Canine Distemper Virus (CDV) and Infectious Canine Hepatitis (ICH). 

This can be carried out 2 weeks after the last vaccination to confirm a puppy is immune.

It can also be used whenever boosters are due to avoid over vaccination because if a pet is already protected against these diseases, there is no need for another inoculation at that point.  

The Leptospirosis Vaccine

The 3 major infectious diseases (CPV, CDV and ICH) are all viruses, and the vaccines made from them typically stimulate a strong immune reaction. 

The leptospires responsible for the disease known as leptospirosis on the other hand are bacteria, and the vaccines made from these (L2 and L4) tend to produce a weak immune response. For this reason manufacturers advise they be given every year. 

A rising number of serious side-effects have been reported following inoculation with L2 and L4 however, and so it is important to think carefully about all the issues involved.

Pet Owners Experiences of Leptospirosis 4

Immune System Support Before and After Vaccinations

Injection Visit given before and after inoculations helps the immune system respond in a healthy manner.

Immunity also helps a puppy's immune system cope successfully with vaccinations, and also to remain strong, healthy and balanced as they grow. This supplement is highly beneficial to give long term to support optimum health.

Giving both of these to pets, in accordance with the guidelines above, helps to ensure that vaccinations are as safe as possible.