Which Shots When & What Are All Those Letters?



  1. How do I know which shot to give my dog or puppy?
  2. What do all these letters mean? 
  3. What is Lepto and when is it dangerous to vaccinate for it? 
  4. What is the difference between a 5 way and a 7/9 way shot? 
  5. What age can I vaccinate for Rabies and how often?
  6. How many shots does a puppy really need?

Do any of these questions sound familiar?

There seems to be a lot of confusion and some very common misconceptions or myths about puppy shots and dog vaccinations, in general. Many of these are addressed in our blog post titled "Puppy & Dog Vaccinations: Myths & Facts".

Here is a breakdown of some of those "cryptic" names/letters on some vaccines:

  • D - Distemper
  • A2 - Adenovirus 2 (includes Hepatitis)
  • P - Parainfluenza
  • Pv - Parvovirus (AKA CPv or Canine Parvovirus)
  • L - Leptospira Bacterin (AKA Lepto, L4 or Leptospirosis)
  • Cv - Coronavirus

How many ways...

The first four are known as core vaccines and are usually given to puppies starting at 4-6 weeks and again every 2-3 weeks until at least 16 weeks old. This is commonly known as a 5-way vaccine. If you're counting letters and wondering how we got 5, the A2 has double coverage for Adenovirus and Hepatitis.

The most common vaccines for years have been the 5-way and the 7-way. The 7-way vaccine was the core vaccines (or 5-way) plus 2 strains of Lepto. You can read more about Lepto here.

Just in the last few years veterinarians and vaccine manufacturers have added 2 more strains of Lepto to the 7-way and it is now known as a 9-way. This is a common annual vaccination for most dogs over 12 weeks. There are two other multi-protection vaccines: the 6-way and the 10-way (formerly 8-way). The 6-way has the core 5 + Coronavirus (Corona) and the 10-way has the aforementioned 9 plus Corona. Your vet can help you decide what coverage is best for your area and your dog.

Click here to see a Vaccination Schedule Chart for dogs.

As always, information given here is meant to be helpful and/or educational. It is, in no way, intended to supersede, challenge or supplant the diagnosis, treatment or advice of a licensed veterinarian.

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