Dog Vaccination Schedule: Core and Optional Vaccines by Age

Vaccinations are the single most effective way to protect your dog from deadly infectious diseases. Some of these diseases, like parvovirus and distemper, have fatality rates exceeding 80% in unvaccinated dogs. The good news is that preventing them is straightforward when you follow a proper vaccination schedule.

This guide covers everything you need to know: which vaccines are essential, which are optional based on lifestyle, the correct timing for puppies and adults, and what to expect at each visit.

Core vs. Non-Core Vaccines: What's the Difference?

Veterinary immunologists divide dog vaccines into two categories:

Core Vaccines

• Rabies: Required by law in most jurisdictions. Fatal once symptoms appear. Protects both your dog and public health since rabies is transmissible to humans.
• Distemper (CDV): A highly contagious viral disease affecting the respiratory, gastrointestinal, and nervous systems. Often fatal, and survivors frequently have permanent neurological damage.
• Parvovirus (CPV): Extremely contagious and devastating, especially in puppies. Causes severe vomiting, bloody diarrhea, and dehydration. Mortality rate in untreated puppies exceeds 90%.
• Adenovirus (CAV-2): Protects against infectious canine hepatitis. Causes liver inflammation, respiratory illness, and can be fatal in severe cases.

Non-Core (Optional) Vaccines

• Bordetella (kennel cough): Recommended for dogs that visit boarding facilities, dog parks, grooming salons, or training classes. Often required by boarding facilities.
• Canine influenza (H3N2 and H3N8): Recommended in areas with known outbreaks or for dogs with frequent social contact.
• Leptospirosis: Recommended for dogs in rural areas or those exposed to wildlife, standing water, or wet environments. The bacteria spread through infected animal urine.
• Lyme disease (Borrelia): Recommended in regions with high tick populations, particularly the northeastern and upper midwestern United States.
• Parainfluenza: Often included in combination vaccines. Recommended for dogs with high social exposure.

Puppy Vaccination Schedule

Puppies receive maternal antibodies through their mother's milk, but these fade between 6 and 16 weeks of age. The challenge is that we don't know exactly when maternal antibodies wear off for each individual puppy, so vaccines are given in a series to ensure protection kicks in as soon as possible.

Adult Dog Vaccination Schedule

After the initial puppy series, dogs need periodic boosters to maintain immunity. The frequency depends on the specific vaccine and current veterinary guidelines.

What to Expect at a Vaccination Appointment

A typical vaccination visit includes more than just the injection. Your vet will perform a brief physical exam, check weight, listen to the heart and lungs, and assess overall condition. This is a valuable health screening opportunity.

Common Side Effects

Most dogs tolerate vaccines well, but mild side effects can occur in the 24-48 hours following vaccination:

• Mild lethargy or decreased appetite (very common, resolves within a day)
• Slight swelling or tenderness at the injection site
• Low-grade fever
• Mild sneezing or runny nose (particularly after intranasal Bordetella vaccine)

Titer Testing: An Alternative Approach

Titer testing measures the level of antibodies in your dog's blood to determine if they still have adequate immunity from previous vaccinations. Some owners and veterinarians use titer testing to avoid unnecessary boosters.

Titer tests are most commonly used for distemper and parvovirus. They cost more than a booster vaccine but can be useful for dogs with a history of vaccine reactions. Note that titer testing is generally not accepted as a substitute for rabies vaccination under most state laws.

Special Considerations

Immunocompromised Dogs

Dogs on immunosuppressive medications, undergoing chemotherapy, or with certain autoimmune conditions may not respond normally to vaccines. Work closely with your vet to create a modified vaccination plan.

Senior Dogs

Older dogs still benefit from core vaccinations. However, your vet may adjust the schedule based on health status and lifestyle risk. A senior dog that rarely leaves the backyard may need fewer non-core vaccines than an active senior that visits dog parks regularly.

Rescued or Unknown History Dogs

If you adopt a dog with no known vaccination history, your vet will likely recommend starting the series from scratch. It's safer to re-vaccinate than to assume protection exists.

For a broader overview of keeping your dog healthy, check out our complete dog care guide. And if you want to understand your dog's ideal body condition, our ideal weight guide can help you assess whether your dog is at a healthy weight.