by Christine L. Merrill, DVM, DACVP, PhD
If you pay attention to the press, you can’t help but notice that more and more people are questioning the necessity of vaccination. The 2014 measles outbreak, which began in an amusement park in California and spread across the United States affecting over 668 people, is a prime example of what happens when we don’t vaccinate. Most of the people contracting measles were not vaccinated. Many of the non-vaccinated patients were children whose parents were concerned about the safety of vaccinating their children and mistakenly believed that measles was no longer a disease of concern in this country. Vaccines administered to our canine companions are equally important to maintain their health and wellbeing and to prevent severe diseases from becoming endemic in our dog population.
Vaccination Primer
What is a vaccine and how does it work? A vaccine is made up of viruses or bacteria that are injected into the body in order to stimulate the body’s immune system to mount a defense against that particular organism. Once the organism is inside the body, cells called macrophages ingest them and carry them to lymphatic tissues which produce antibodies, pivotal in the destruction of the infectious agent. The viruses or bacteria in the vaccines are non-infectious (heat killed or modified live so they can’t reproduce) which is why our pets don’t contract the actual disease when injected. Some animals will experience a decrease in appetite or lethargy (tiredness) after vaccination, but that is usually due to the immune system response and is short-lived.
Which vaccines does my dog need? Your veterinarian will assess the life stage and lifestyle, risk of exposure, and underlying medical conditions of your dog to decide which vaccines are best. Core vaccines are those that are generally recommended for all dogs and include rabies, parvovirus, distemper virus and adenovirus. Of the noncore vaccines, Bordetella bronchiseptica is one of the most commonly used, as many boarding facilities and canine competitions require proof of vaccination prior to entry. Depending on where you live, other noncore vaccines may be recommended such as Leptospira interrogans or Borrelia burgdorferi (Lyme disease).
For the core vaccines (excluding rabies), puppies should be vaccinated three times, once every 4 weeks between the ages of 6 and 16 weeks. If puppies successfully nurse during the first 2 days of life, they receive the dam’s colostrum. Colostrum is chock full of maternal antibodies that are absorbed through the gut of the puppies and provide protection against diseases. 
These same colostrum-derived antibodies will prevent the puppies from mounting an immune response to a vaccine until the age of 6 weeks, which is why vaccines aren’t given prior to 6 weeks of age. After the initial series of puppy vaccines, a booster should be given no later than 1 year after, and revaccination should occur every 3 years thereafter. Check with your veterinarian to make sure that this timeline is appropriate for your dog based on the type of vaccines being used. For rabies vaccines, state regulations will govern the frequency of administration. There are 1 year or 3 year rabies vaccines which are administered no earlier than 12 weeks of age, unless there are extenuating circumstances, like a severe outbreak of rabies in your area.
Please make sure that you protect your dog and those in your community by staying up to date on needed vaccinations. The diseases we vaccinate against can cause severe illnesses, death, and some are even contagious to humans (rabies and leptospirosis). Greater than 98% of vaccinated dogs develop a protective immune response, and serious postvaccinal adverse reactions are considered to be uncommon. If you would like to know more, there is an excellent guideline of canine vaccinations available in the American Animal Hospital Association website – click on the link at bottom of the page: (https://www.aaha.org/professional/resources/canine_vaccine.aspx#gsc.tab=0).