Vaccinating Puppies - Little Critters Veterinary Hospital - Gilbert, AZ

Little Critters Veterinary Hospital

1525 N Gilbert Road Suite #C-101
Gilbert, AZ 85234


VACCINE THEORY - How they work:

Puppy Care at Little Critters Vet

The pet and veterinary community has hotly debated the correct vaccination protocol for our pet dogs. In the past it was thought that any disease that a vaccine available to fight it should be given to our pets. As a backlash to this rational many articles in the pet community portrayed vaccines as the enemy and a likely cause of disease. The opinion of the veterinary community and certainly my opinion is a mixture of these two thoughts. And this article is intended to provide a rational for safe and reasonable vaccination of our pet dogs.

Okay, so what a vaccine is:

There are many types of vaccines available in human and animal medicine but currently many of our dog vaccines are modified live vaccines. This means that the scientist has slightly altered the virus so that it will still stimulate immunity but will not be able to cause disease in the patient, thus creating a safer vaccine. Immunity is just the body’s natural defense against infection.

What a vaccine isn’t:

Vaccines do not prevent disease in those animals already exposed to the virus. The vaccine must be present prior to exposure to provide time to grown adequate memory cells to aid in defense of the body. So, if you have a puppy that was exposed to parvo virus but not yet ill a vaccine will NOT prevent disease.

How vaccines work:

So many of us haven’t always understood why we need to vaccinate our pets (or children) we are just doing what is recommended by the doctor in an attempt to keep our loved one safe. As a veterinarian, I believe that it is important that owners understand why we vaccinate so that they have informed consent and know what they are protecting their pet with and against. By giving a vaccine we are attempting to stimulate the dog’s immune system to create memory cells that will be saved in the body to fight the virus if they encounter it in the future. On the initial exposure to a virus (antigen) the immune system will create a few short lived memory cells but will not create lasting immunity. Therefore, we always provide one booster in 2-3 weeks to give a second boost to the immune system and create millions of long lived memory cells in the body. These cells are constantly circulating in the body looking for foreign invaders to attack and destroy thereby defending the body and providing the pet immunity to the virus.

Why are puppies given several vaccines?

Neonate puppies or those recently born, receive all of their immunity from their mother through the uterus and the milk. The amount and level of immunity they receive is entirely dependent upon the mother’s vaccination and immunity status. Therefore a mother who has been poorly vaccinated, or even never vaccinated, will give poor immunity to her pups and those pups are at a very high risk of contracting and dying from very early infections such as parvo virus. So, the mother’s immunity is very important in providing her pups early immunity from disease. The mother’s immunity will also block and prevent our vaccine from providing vaccinated immunity to the puppy. Also, based on her level of memory cells the mother’s immunity may last from a few weeks in the pups to as long as 4 months. This means that your newly purchased 8 week old puppy may or may not have immunity to infection. Without several costly blood tests, the best way of ensuring the puppy is protected is sequential vaccines over time.

But as we’ve said the mothers immunity blocks our vaccines so how do we know when her immunity is low enough for our vaccine to work but not so low that the pup is entirely unprotected? As we’ve learned puppies early in life are likely to be protected even from an infrequently vaccinated mother, therefore we do not typically need to vaccinate prior to 6 weeks of age. So we know that the best time to begin vaccines is from 6-8 weeks of age catching those pups that have limited or short term immunity. However some of these pups may have long immunity preventing our vaccine from working and preventing the puppy from receiving long lasting immunity to disease. The best way around this is to do sequential vaccines every 3 weeks for a series of 4 vaccines up to age 4 months. By doing this we are ensuring that the pups who have lost early immunity are protected at the proper time and we are also ensuring that the pups with longer lasting immunity are vaccinated long enough for our vaccine to work and a boosters to be given.

Summery to why sequential vaccines are needed in pups:

  • Start vaccines at 6-8 weeks
  • Vaccinate every 3 wk up to 4 months old
  • This will ensure early protection
  • This will ensure the best lasting immunity
  • Provide an additional vaccine booster at 18 months of age.
  • It is important to understand that even though there is a debate in our community about vaccinating adult animals that debate should not involve immature animals. The ONLY way of ensuring protection from deadly disease in puppies is to vaccinate them properly up to 1 year of age. At that point we have given them long lasting memory cells and may consider extending the subsequent intervals to every 2-3 years depending on the level of exposure and the vaccine used. Please vaccinate your puppies.

The most common or core vaccine: Da2p-cpv:

Distemper virus is an often deadly upper respiratory and neurological virus of dogs.

  • Adenovirus type 2 is a hepatitis virus of dogs
  • Parainfluenza is a respiratory infection often involved in kennel cough complex
  • Parvo Virus is often a fatal gastrointestinal infection of all poorly vaccinated dogs.

This is the core combo vaccine that is given to puppies every 3 weeks until 4 months of age. It protects against the worst diseases that often are life threatening to puppies.

1. Canine Distemper Virus: is a disease of dogs only (although dogs can infect ferrets). The disease causes a variety of clinical signs from purulent (pus) nasal discharge and eye discharge with coughing to vomiting, diarrhea and seizures. Infected pets are often febrile (fever >103F) and very depressed/lethargic. The prognosis is very poor.

2. Canine adenovirus type 2: is also called canine infectious hepatitis and is a very serious disease that often isn’t seen in our area due to vaccination, but once was very common. There is also a type I vaccine that we don’t use because type 2 will protect against both types and type I vaccine causes eye inflammation commonly called blue eye.

3. Parainfluenza: is a dog disease that is part of the kennel cough complex. The virus works with the bordetella bacteria to cause a harsh unproductive cough. These pets typically have a history of exposure to other dogs (often in a kennel situation) and are typically normal except for a cough. They often respond well to treatment and supportive care.

4. Canine Parvo Virus: Is a life threatening disease of puppies and potentially of unvaccinated adults. The virus infects the rapidly growing cells of the intestine and causes severe liquid bloody diarrhea, frequent vomiting and very depressed/lethargic puppies. Puppies that are not treated will usually die. This disease can be prevented by vaccination.

Additional Vaccines (many and varried depending on where you live in the US and thus your pet’s exposure to disease). A few commonly used:

  • Corona Virus: This is given twice to puppies 3 weeks apart. The virus causes a disease of vomiting and diarrhea in very young puppies. This vaccine is typically not given to adult dogs.
  • Bordetella Bacterin:Protection from kennel cough complex. Is given as nose drops in our hospital and only to those dogs at high risk such as boarding dogs, those that attend puppy school and those that frequent doggie parks should also be vaccinated.
  • Rabies:Frequency will vary by state. In AZ it is given to puppies and a booster is given in 1 year of age and then again every 3 years.


What is it? A simple blood test done in our hospital with same day results will give us an idea of what degree of protective immunity your dog has to fight canine parvo virus, canine distemper virus, and canine adeno virus. If your dog is low on protection for either distemper or parvo we can then give a monovalent (single virus) vaccination only for that disease. This allows us to limit the frequency and number of vaccines for adult dogs.