There are generally two broad types of pet vaccines:

1. Core vaccines include the only legally “required” vaccine which is for Rabies and other important though not legally required vaccines such as the DHPP combo vaccine (often referred to as “puppy shots” since initial doing requires 2-3 boosters @ 3 weeks apart).  Core vaccines have a record of safety and effectiveness.  Young pets are especially vulnerable to disease, so should get the ‘core’ vaccines.  As pets age, or if there is a history of a vaccine reaction, discuss risks of re-vaccination with your vet. 

2. Non-core vaccines (Lyme, flu) can offer added protection for certain diseases if your pet is considered highly exposed/at risk. These are not required and so may be worth considering weighing the risks and benefits to you pet based on their exposures and health characteristics. 

Multiple pet vaccinations are routinely offered/recommended by most veterinarians on an annual basis, and/or may be offered if ‘past due’ when a pet is brought to vet for a visit. While risks and requirements of most ‘annual vaccines’ is a somewhat controversial topic, it’s general agreed that pet should NOT be given a vaccine if sick.  There is also suggestion that multiple vaccinations should not all be given ‘same day’ to reduce impact on immune system.  Read more: Are you Over-Vaccinating Your Dog or Cat? – The Pet Health and Nutrition Center

More details on types of vaccines:

Required Core Vaccine - Rabies 

The Rabies vaccine is the only pet vaccine required by law as the disease can be transmitted to humans and is typically fatal.  The first can be given by 4 months of age – it is a single vaccine good for 1 year.  The next year a “3 year” Rabies can be given so long as written proof of prior vaccine is available.  As long a documentation is kept available the Rabies vaccine can therefore become a “3 year vaccine for the life of the pet’  - avoiding annual vaccines when a 3 year is acceptable can save both money and unnecessary overvaccination.

Other “core vaccines” 

Though not required by law, are recommended to protect against highly contagious and potentially life-threatening diseases.  They may even be required by some boarding facilities, dog parks, or pet groomers.  As puppies and kittens are at higher risk of diseases and have undeveloped immune systems, most vets, animal welfare organizations, and breeders will provide/recommend the combo vaccine as ‘puppy shots” or “kitten shots” include a series of 2-3 boosters usually given 2-4 weeks apart.  Most vets recommend this annually thereafter; some vets offer a 3-year version. These shots can include a variation of 4-7 combinations:

• A common example is the 4 combo DHPP (distemper, hepatitis, parvovirus, and parainfluenza) for dogs.

• A vaccine for leptospirosis (a life-threatening disease caused by a bacteria often in outdoor water or soil) may be given separately or added to the combo (DHPPL). 

Non-core vaccines.

Non-core vaccines are not required by law but may offer a third tier of protection for unique exposures due to lifestyle, environment, travel habits, and or local disease.   As not all dogs are likely to be affected by these diseases, you may decide a vaccine is not appropriate. The vaccines are annual and can be given at any time if exposure/risk conditions change.

Examples of non-core dog vaccines include:

• Bordetella (kennel cough, a highly infectious ‘cold like’ illness that can be passed).  The vaccine is recommended if your dog goes in areas where other dogs are present as the infections may not always be noticeable at first (boarding, groomers, play parks, pet stores).  The vaccine may be internasal is given annually or as needed.  It is somewhat effective to reduce at least severity and length of disease.   

• Lyme disease – this vaccine is for a specific tick-borne illness (as opposed to a disease infectious between dogs.  Tick prevention products may reduce the risk of Lymes disease in dogs. To maximize its effectiveness the vaccine must be given twice (booster). The vaccine may be more expensive than core vaccines.

• Canine influenza.   This vaccine may be warranted for unique exposure concerns. The vaccine may be more expensive than core vaccines.