Infectious diseases and vaccines for your dog

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Infectious diseases and vaccines for your dog - a dog being vaccinated by a vet

Routine vaccinations are an important part of owning a dog and keeping them healthy. However, not all dogs need every available canine vaccine. Read on to learn the answers to questions such as:

  • When should I vaccinate my dog?
  • What can my dog be vaccinated for?
  • Can dogs have vaccine reactions?
  • What diseases can my dog not be vaccinated for?
  • Why should my dog be vaccinated?

It is important for pet parents to discuss the right vaccination schedule for their dogs with a veterinarian. The vaccination schedule, required vaccines, and frequency of vaccination varies for every dog.

When are dogs vaccinated?

Before your dog can be vaccinated, a veterinarian needs to ensure they are healthy enough to receive the vaccine. Dogs also need to be old enough for a vaccine to be safe and effective. Young puppies under the age of 12 to 16 weeks still have their mother’s antibodies which provides some protective immunity against diseases that the mother has been exposed to or vaccinated for in the past. However, these same antibodies that protect young puppies also work against vaccines, rendering them less effective. The exact age when maternal immunity wears off varies between puppies, which is why puppies receive a series of boosters over several weeks.

Puppies can begin vaccinations as early as six to eight weeks of age and complete the series by the time they are four to five months old. Every dog is different in terms of when their maternal immunity wears off, when they receive vaccines, and their immune reaction to them. The timing of vaccinations for adult dogs is based on their vaccine history, health status, and lifestyle. The bottom line? Talk to a vet about the best time to vaccinate your dog.

What infectious diseases can dogs be vaccinated for?

Vaccinations for dogs are categorized into core and non-core or risk-based vaccines. It is recommended that all dogs receive the core vaccines, while a dog’s age, pre-existing conditions, geographic location, and lifestyle affect which non-core vaccines are recommended.

Canine core vaccines

It is recommended that all healthy dogs receive core canine vaccines. Many of the diseases covered by the core vaccines are highly contagious and potentially deadly.

DAP or DAPP vaccine (“distemper combination”)

The distemper combination vaccination offers protection against distemper, adenovirus, parvovirus, and sometimes parainfluenza. The vaccine is sometimes called a four-in-one vaccine due to its coverage of four diseases. The vaccine can be administered to puppies as young as eight weeks of age and is boosted every two to four weeks until two doses have been given after the age of 12 weeks. Adults with no known history of prior vaccination are given an initial series of two doses over a period of two to four weeks. The vaccine is boosted a year after the final dose, and the following boosters can be given every three years. The vaccine covers:

Parainfluenza is not always included in this vaccine and is sometimes not considered a core vaccine in dogs.

Rabies virus

Rabies is rare in pet dogs but has a nearly 100% fatality rate. The virus, spread by a bite from a rabid animal, attacks the brain, causing aggression, fever, hypersensitivity, foaming at the mouth, seizures, and disorientation. The disease is also zoonotic, so humans can catch it from infected dogs and other animals. The rabies vaccination is legally required for all pet dogs in many places due to its risk to people and other animals. A single dose of the rabies vaccine is given after 12 weeks of age, boosted a year later, and then boosted again every three years.

Canine non-core vaccines

Non-core vaccines are given largely based on a dog’s overall lifestyle and where they live.


Bordetella is one of dozens of agents that cause kennel cough. This respiratory disease is highly contagious but usually not life-threatening. Symptoms of kennel cough include a dry honking cough, gagging, coughing up phlegm, fever, and nasal discharge. The schedule for administering  the bordetella vaccine depends on the type of vaccine. In general, one or two initial doses are given two to four weeks apart as early as eight weeks of age and then boosted every six to twelve months. The Bordetella vaccine is recommended for dogs who are in close contact with other dogs and is required by many boarding and grooming facilities.


Leptospirosis is a bacterial infection spread through contaminated urine on the ground and in standing water. The disease is also zoonotic, so humans can be infected following exposure to a sick dog’s urine. Signs of illness include excessive urination, excessive thirst, weakness, lethargy, jaundice, vomiting, diarrhea, and difficulty breathing. Two initial doses of the vaccine are given two to four weeks apart as early as 12 weeks of age and then boosted annually. The leptospirosis vaccine is sometimes mixed in with the distemper combo vaccine and given as a single five-in-one injection. This vaccine is recommended for dogs who live in areas around a lot of wildlife or who have access to ponds, ditches, or other types of standing water.

Lyme disease

Lyme disease is a tick-borne illness that can cause lameness, fever, fatigue, swollen lymph nodes, swollen joints, and loss of appetite. Two initial doses of the vaccine are given two to four weeks apart and it can be boosted annually. The exact age that is safe to begin the vaccine series depends on the manufacturer. It is recommended that dogs who live or travel to Lyme-endemic areas or are otherwise exposed to ticks receive the Lyme disease vaccine.

Canine influenza virus

Canine influenza infection in dogs has symptoms similar to the flu humans experience, but it is not the same virus. The disease is spread through respiratory secretions, so dogs who are in close contact with other dogs may receive the vaccine regularly. Canine influenza symptoms include a cough, runny nose, fever, lethargy, eye discharge, and reduced appetite. Two initial doses are given two to four weeks apart after 12 weeks of age and then boosted annually.

Snake bite vaccine

The Crotalis atrax toxoid vaccine, also known as the snake bite vaccine or rattlesnake vaccine, protects against the venom of the western diamondback rattlesnake found in the Southwest area of the United States and parts of Mexico. Two initial doses are given one month apart followed by an annual booster approximately one month prior to anticipated snake activity (usually in the springtime).

What vaccine reactions can dogs have?

Immune responses to vaccines are normal and a sign that a dog’s immune system is doing what it is supposed to. Adverse reactions are different and are much rarer. Symptoms of a normal immune response include:

  • Low-grade fever
  • Pain at injection site
  • Muscle aches
  • Lethargy
  • Lack of appetite

A dog will normally feel better less than 24 hours after their vaccines, and some don’t show any signs of vaccination at all.

Adverse reactions to vaccines include:

Adverse reactions are rare and vaccines are predominantly safe. The risk of disease is much higher than the risk of a dog experiencing an adverse vaccine reaction. In addition, a dog cannot catch a disease from the vaccine itself. If your dog shows symptoms of an adverse reaction, contact your veterinarian. Your dog may not require treatment, but reporting of adverse reactions following vaccinations is important.

What infectious diseases in dogs do not have a vaccine?

Most infectious diseases in dogs do not have vaccines. Some that are spread by insects, such as fleas, ticks, and mosquitoes, can be prevented with monthly preventive. Some examples of common infectious diseases that a dog cannot be vaccinated against include:

Flea, tick, and heartworm prevention can prevent diseases and internal parasites caused by these insects. Many preventatives also prevent scabies, mange, and ear mite infections.

Do dogs really need vaccines every year?

Not all canine vaccinations are given on an annual basis. The core vaccines, which include the DAPP combo vaccine and the rabies vaccine, are given every three years after the initial boosters. Other risk-based vaccines may be recommended annually based on your dog’s lifestyle and where you live. Work with a veterinarian to develop a vaccine timeline that works for you and your dog.

Why vaccinate?

Canine vaccines prevent highly contagious and dangerous diseases in people as well as dogs. For example, most cases of rabies in humans result from exposure to dogs and cats, and leptospirosis can spread to people from infected pets. Vaccinating the majority of dogs in a community creates herd immunity and protects not only the vaccinated dog but other dogs in the area, such as young puppies and immunocompromised dogs. Vaccines are safer and more affordable than treatments for the diseases they prevent. If you would like to talk to a vet about your dog’s vaccination needs, you can schedule an online virtual care appointment with a vet today.

FAQ - Infectious diseases and vaccines for your dog

What are the most important vaccines for dogs?

The rabies vaccine and the distemper combination vaccine, covering distemper, adenovirus, parvovirus, and sometimes parainfluenza, are the core vaccines for dogs. These diseases are highly contagious and often deadly. Additional vaccines are risk-based and may be needed based on your dog’s lifestyle and where you live.

What is the seven-in-one vaccine for dogs?

Calling a vaccine seven-, five-, or four-in-one is not specific and can vary from manufacturer to manufacturer. Instead, check to see what diseases the vaccine covers and discuss which vaccines your pet needs with a vet.

What is the proper vaccination schedule for a puppy?

A puppy can begin receiving vaccines around six to eight weeks of age, though the starting age will vary from puppy to puppy. Puppies need to receive all of the core vaccines by the time they are around 16 weeks of age as long as they are healthy enough to do so. Discuss the right vaccination timeline and what risk-based vaccines your puppy may need with a veterinarian.

What are the first signs of parvo in a dog?

The most common signs of parvo in a dog are severe vomiting and foul-smelling, liquid diarrhea. Both the vomiting and diarrhea may contain blood and the ill dog may be lethargic and unable to eat.