puppy shot schedule - the importance of vaccination

Puppy Shot Schedule: Importance of Vaccination

Among the countless diseases that are known to affect our beloved pet dogs, a good number of them are highly preventable with good nutrition, daily exercise, and regular veterinary visits that will help identify the presence of risk factors that can lead to the development of such diseases. However, one of the most important, albeit often overlooked aspects of optimum canine health is vaccination. Dogs, especially puppies, need to be vaccinated against some of the more serious forms of canine diseases so that they will be allowed to grow and develop as optimally as possible. In this post we shall take a comprehensive look at a puppy shot schedule and gain a much deeper understanding on the importance of vaccination.

What are Vaccines?

Before we look at the puppy shot schedule, it is important to have a clear understanding of how the immune system works and how vaccines can play a role in the different functions of the immune system.

vaccinate a puppy

The principal function of the immune system is the destruction or inactivation of a substance that it considers as a threat. It mobilizes a variety of immune system cells that perform a host of functions. When there is an unknown substance called antigen, the immune system will mobilize a host of lymphocytes that will attempt to destroy the antigen often in conjunction with other immune system cells. This takes time because it is the first time that the immune system has encountered this particular antigen or ‘threat’. As the threat is slowly neutralized by antibodies that are produced in response to the presence of the antigen, another group of lymphocytes will begin making a copy of the antibodies.

When another threat presents itself which has the same, exact antigenic profile as the first infection, the memory cells of the immune system will automatically recognize the antigen and start producing the antigen-specific antibody needed to eliminate the threat. In effect, the second time an infection of the same nature occurs, the immune system will already have a more specific, faster, and more efficient mechanism to fight the antigen.

Vaccines are antigens. These are either killed, weakened, or fragments of a bacteria, virus, or any other microorganism that are designed to simulate the entry of a pathogen or an antigen without necessarily causing the expression of the clinical disease. This is because they are so weak that the immune system cells can easily defeat them so the clinical manifestations are very minimal, if not totally absent. At the same time, memory cells go to work and make copies of the antibodies that were produced from the subclinical vaccine-induced infection.

When there is a ‘real’, non-vaccine antigen or the actual virus or bacteria itself, the immune system already has the antibodies to fight it so an infection is effectively prevented.

This is how vaccines work.

What are the Different Types of Vaccines?

Every time scientists work on developing or formulating a vaccine, they have to consider how the immune system typically responds to the antigen. If memory cells cannot be produced because of a different kind of disease-causation, then there is no way that a vaccine can be produced.

Scientists will also consider the population which needs to be protected. If the disease only occurs in very few dogs, then there is not a chance that the vaccine will be produced for practical reasons. However, if the disease affects a great number of dogs across geographical boundaries, then a vaccine is necessary to help curb the incidence of such a disease.

Lastly, scientists will also take a look at the approach or technology that is best suited for the creation of the vaccine. Depending on the antigen that is used, different techniques of vaccine formulation have to be used.

Given these three important considerations that scientists have to keep in mind when developing a vaccine for puppies and dogs, we can look at the 4 different types of puppy vaccines.

  • Live-attenuated vaccines 

These are made from substantially weakened forms of microorganisms. They are preferred because they carry the entire organism that causes the disease. However, because it is so weak, the immune system will not have any problems fighting it and creating memory antibodies. Unfortunately, if your puppy has a very weak immune system or your dog has a compromised immune system, this weakened form of microorganism can cause a full-blown disease. That is why it is imperative that your veterinarian evaluate the immune system functioning of your puppy before administering any of this type of vaccine. On a positive note, these vaccines provide the strongest and longest-lasting protection for your dog.

Examples of these are canine parvovirus vaccines, adenovirus type 2 vaccines, and most vaccine brands for canine distemper virus.

  • Inactivated vaccines 

These vaccines are similar to live-attenuated vaccines except that the microorganisms have been purposely killed. In live-attenuated, the microorganisms are alive but very weak. As such, you will need several shots of this type of vaccine to confer the kind of immune protection that you can obtain from a live-attenuated vaccine.

Examples of puppy vaccines of this type include vaccines for rabies, leptospirosis serovars 2 and 4, bordetella bronchiseptica, and influenza. Some vaccines for Lyme disease or Borrellia burgdorferi are also examples of inactivated or killed vaccines.

  • Recombinant, conjugate, subunit, and polysaccharide vaccines 

These vaccines carry only a part of the microorganism. It can be its protein structure, its sugar composition, or even the casing that surrounds it. The good news is that these vaccines provide very strong immunologic response but only on the targeted parts of the microorganism. These can be given to puppies that have weak immune system as well as dogs with chronic health problems. The issue is that you will need booster shots to make sure your puppy or dog is adequately protected at all times.

Examples of this type of vaccine include recombinant vaccine for the canarypox virus-vectored distemper virus and Lyme disease expressing the OspA plasmid.

  • Toxoid vaccines 

These vaccines are produced from the toxin synthesized by a microorganism that is known to cause a specific disease. In an active infection, the vaccine targets the toxins released by the microorganism and not the microorganism itself. These will also require booster shots.

An example of toxoid vaccine for puppies and dogs is the Crotalus atrox toxoid vaccine which is synthesized from the toxins produced by the Western Diamond rattlesnake.

Why Do My Puppies or Dogs Need to Be Vaccinated?

Based on the foregoing discussion, it is clear that vaccinations are nothing more than a training exercise for the puppy’s or dog’s immune system to allow it to respond more efficiently, more swiftly, and more decisively in the case that a real pathogen for which it has been ‘trained’ for presents itself. This sets the tone for the various benefits of vaccination for puppies and dogs.

  • Prevent pet illnesses 

While vaccines do not cover every single canine disease known to man, they provide protection against some of the more common illnesses that affect man’s best friend. This alone can already have significant implications. It helps your puppy grow and develop into a healthier and better-rounded hound than if it were not vaccinated. Of course, you will still have to worry about other diseases that are not covered by vaccines. At the very least, you are doing yourself a favor by substantially reducing the number of canine illnesses to worry about.

  • Avoid costly treatments 

When dogs get sick, they require the utmost attention and highly specialized care. They are not like us who can readily pop a pill whenever we feel we’re going down with a fever or even flu. More often than not, our dogs will already be in the advanced stages of their infections before we even realize that they are sick. Advanced illness stages typically command a handsome bill from your vet. Like they say, a pound of cure is worth an ounce of prevention. If you can save yourself from literally hundreds to thousands of dollars for the treatment of a single dog disease, what’s spending a couple tens of dollars to help ensure your dog is protected from such a disease? That’s just the treatment part. We haven’t talked about other expenses like veterinarian’s fees, laboratory and diagnostic fees, and even veterinary hospitalization costs.

  • Prevent transmission of disease to man and other pets  

If you have a multi-pet household, having a single pet that is sick increases the risk of the other pets getting sick, too. Unfortunately, the story doesn’t end there. In some cases of canine infections or illnesses, the germs that are present in our dogs can be transmitted directly to us when we allow them to lick us, kiss us, or even as simple an act as hugging them. The point is that if one of your pets is sick and it so happens that it can be transmitted to other pets or even to you and your family, then you’re looking at a potentially costly situation.

  • Denotes social responsibility 

Dogs carry with them certain microorganisms that can be passed in the environment. If you can prevent these microorganisms from ever infecting your dog, then you also contribute to the health of the entire community. Another instance is rabies. It is our responsibility as pet parents to have our dogs vaccinated against rabies to help promote our being responsible members of society. We owe it to ourselves and the people around us to protect our dogs against rabies.

  • Required by law

There are now laws, either local and state, that call for the vaccination of pets. Rabies is just one of them. Vaccinating our pets not only makes us responsible neighbors but law-abiding citizens as well.

When Should My Puppy Be Vaccinated and Against What?

Puppies that obtain their milk from their mothers are generally protected from diseases because of the rich maternal antibodies present in breastmilk. Puppy shots are typically initiated between 6 and 8 weeks of age. Booster shots are usually given every 2 to 4 weeks until such time that the puppy reaches 16 to 17 weeks. However, there are some instances or breeds of dogs like the black-and-tan breeds that may require booster up to the age of 20 weeks. As always, it is imperative that these vaccinations are evaluated by your veterinarian since puppies, like humans, react differently to the same vaccine.

The following is the current recommendation for puppy shots:

  • Puppies aged 6 to 8 weeks – distemper and parainfluenza vaccines with an optional bordetella vaccination.
  • Puppies aged 10 to 12 weeks – parvovirus, distemper, parainfluenza, and adenovirus or canine hepatitis vaccines (collectively called DA2PP vaccine) with optional vaccination against coronavirus, Lyme disease, bordetella, and leptospirosis
  • Puppies aged 12 to 24 weeks – rabies vaccine
  • Puppies 14 to 16 weeks – DA2PP vaccine with optional vaccination against coronavirus, Lyme disease, and leptospirosis
  • Puppies 12 to 16 months – rabies, DA2PP vaccine with optional vaccination against coronavirus, Lyme disease, bordetella, and leptospirosis
  • Every 1 to 2 years – DA2PP vaccine optional vaccination against coronavirus, Lyme disease, bordetella, and leptospirosis
  • Every 1 to 3 years – rabies vaccine

What are the Diseases that My Puppy Needs to Be Vaccinated Against?

In the preceding section we had a glimpse at the vaccinations that your puppy should be receiving from the moment it reaches the age of 6 weeks until about age 24 weeks with some being booster doses. If you have noticed there are certain vaccines that are written as optional. What this means is that you may or may not give these vaccines to your puppy at all. The rest of the vaccines are considered mandatory and as such all puppies are required to be vaccinated against those diseases. We can thus classify these vaccines as either core or optional. This also gives us an idea of the implications of the diseases for which these vaccines are designed to prevent.

Diseases Requiring Mandatory Vaccinations 

  • Distemper virus infection

Canine distemper is a highly contagious and very serious disease that is caused by the canine distemper virus, a relative of the human measles virus that targets the cells and tissues of the nervous, respiratory, and gastrointestinal systems of dogs. It can lead to severe diarrhea, paralysis, seizures, and death. Currently, there is no cure for canine distemper.

Distemper vaccination is initiated at age 6 to 8 weeks, repeated every 2 to 4 weeks, then a final booster at 12 months.

  • Adenovirus canine hepatitis  

In humans, viral hepatitis is caused by a variety of hepatitis viruses although hepatitis A, B, and C viruses are very common. In dogs, they are not affected by hepatitis viruses. Instead, the organism that brings viral hepatitis is an adenovirus. Mild forms of hepatitis may not be fatal. However, the severe forms almost always kill. There is no cure for canine hepatitis; only symptomatic management is available.

The vaccination against adenovirus canine hepatitis coincides with the administration of distemper vaccine – start at 6-8 weeks, repeat every 2-4 weeks, and boost at 12 months.

  • Parvovirus infection

Puppies that are most vulnerable to the deadly effects of parvovirus infections are those younger than 4 months old. They may not experience neurologic symptoms but death usually ensues from extreme dehydration, usually within 48 to 72 hours. Again, there is no known cure for parvovirus infections which are very common among unvaccinated dogs leading to severe vomiting and bloody diarrhea.

Like distemper and adenovirus canine hepatitis vaccinations, parvovirus vaccines are given as soon as the puppy reaches 6 weeks old, repeated every 2-4 weeks, then given a booster shot at 12 months.

  • Rabies

Everyone knows what rabies is. This central nervous system infection causes excessive drooling, hydrophobia, hallucinations, and paralysis eventually leading to death. Depending on existing rabies vaccination rules in your state, it can be given as early as 12 weeks, a booster shot at age 12 months, and then booster shots every 1-3 years depending on your state.

Diseases That Have Vaccination as an Option

  • Bordetella kennel cough

There are many causes of kennel cough, medically known as infectious tracheobronchitis. This can be brought about by Parainfluenza virus and by Bordetella bronchiseptica that attack the lining of the dog’s respiratory tract producing inflammation. The irritated airways stimulate the cough reflex in an attempt to ‘dislodge’ whatever is ‘present’ in the airways. Unfortunately, this also makes dogs more vulnerable to secondary infections because the ciliary defense mechanism is faulty. It is mostly common in the summer although kennel cough can occur anytime.

The vaccines for parainfluenza virus are typically included in multivalent preparations that include adenovirus canine hepatitis vaccine, canine distemper vaccine, and parvovirus vaccine. That is why these are collectively called DA2PP vaccines. As for Bordetella bronchiseptica, you can opt to give a vaccine against this microorganism at age 6-8 weeks, repeated after 4 weeks, then boosted at 12 months to be repeated every 1 to 2 years.

  • Leptospirosis

Leptospirosis is a zoonotic infection that can be transmitted from infected animals to humans. Leptospira are found in both soil and water and have a worldwide distribution. The threat is mostly associated with rat feces and urine and can infect man as well as other animals. This can lead to severe weakness, muscle pain, jaundice, and even kidney failure. There are powerful antibiotics that have been proven effective against spirochetes.

If you don’t want to spend that much on antibiotics, you may want to have your pet vaccinated against leptospirosis starting at the age of 10 weeks to be repeated after 4 weeks then a booster at 12 months plus repeat dosage every 1 to 2 years.

  • Coronavirus infection

Coronavirus infections are considered mild especially when compared to the others in this list. It causes mostly gastrointestinal symptoms like diarrhea, vomiting, and loss of appetite. However, it can also cause respiratory problems. If you’re worried about such an infection in your puppy, then you can start giving your pet coronavirus vaccines at 10 weeks, repeated after 4 weeks, boosted at 12 to 16 months, and then boosted again every 1 to 2 years.

  • Lyme disease

This disease is caused by the spirochete Borrelia burgdorferi and is transmitted by the black-legged tick which is quite common in the northeast regions of the US. Unlike the Lyme disease in humans, however, there are no telltale symptoms of spotting or the bull’s eye rash that is a well-known attribute of the disease. But, it does cause limpness, lymph node swelling, fever, and loss of appetite. If not managed, it can lead to a variety of neurologic problems. Vaccinating your puppy against Lyme disease can be done together with vaccination against kennel cough and leptospirosis.

puppy vaccination

Some Tips for Maximizing the Benefits of Vaccination for Your Pup

Vaccinations are only a part of the solution to ensuring your puppy’s optimum health and freedom from certain diseases. However, there is only so much that vaccines can do. Here are a few tips on how you can maximize the benefits of vaccination for your pup.

  • Always start with a discussion with your vet. He will need to make a thorough assessment of your puppy to determine the appropriateness of the different types of vaccines.
  • Don’t ever think that getting one or two shots will already confer life-long immunity for your dog. As we have already explained above, many of these vaccines need to be repeated after some time to help keep the levels of antibodies in your growing puppy substantially high.
  • Be prepared to manage minor issues associated with vaccinations such as discomfort, pain, or even loss of appetite. These should not discourage you from giving the next shot for your puppy.
  • Take the necessary steps to avoid exposing your dog to possible sources of infections, although it has been vaccinated. Keep your surroundings clean as many of these germs are only lurking around us.

Vaccinating your puppy should be every pet parent’s solemn responsibility. We owe it to our pets to protect them against the harm brought about by highly preventable diseases. If something can be done to prevent such a disease from occurring, why wait for the actual disease to occur before you act? That time is now while dogs are still young and they still have a very bright future ahead of them.

Related Post: Best Pill Shooter for Dogs


  1. Vaccinations, AVMA
  2. Vaccinations for Your Pet, ASPCA
  3. How Often to Vaccinate a Dog or Cat, Best Friends Animal Society


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