The subject of canine vaccination is currently under scrutiny. It used to be unquestioned. Your puppy would undergo a rigorous series of shots to proect it from numerous diseases, usually bundled into one shot administered at two-week to three-week intervals beginning at eight weeks of age. Not anymore. Like all fields, veterinary science has evolved and changed, and numerous health problems in our dogs may indicate that we have taken all this vaccinating too far. Serious side effects have been linked to the number and types of vaccines administered, and in recent years, studies have shown that routine vaccinations are effective far longer than originally thought.

So-called live viruses are weakened miniscule amounts of the virus itself, insufficient to give your dog the disease unless it has a weakened immune system. Killed vaccines are more stable, but they do not offer the same strong protection as the live variety and have to be given at more frequent intervals. It is now believed that the vaccines themselves, whether live or killed, and the practice of automatic yearly boosters, could harm a dog's immune system, triggering autoimmune diseases. Other serious side effects have been observed as well, among them anaphylactic shock, occurring most frequently among small dogs, as well as infections at the site where the vaccine has been injected.

Five years ago, bucking the knee-jerk practice of annual shots for our dogs, Dr. Ronald Schultz of the University of Wisconsin instead recommended an “every three- or more-year” vaccination schedule for cats and dogs. The Colorado State University Veterinary Teaching Hospital reinforced this change by announcing a new vaccination protocol. The American Animal Hospital Association (AAHA) followed suit, encouraging individual dog owners to work with their vet to devise the best program for their dog.

This trend was also reinforced by the American Veterinary Medical Association (AVMA), which agrees that “unnecessary stimulation of the immune system does not result in enhanced disease resistance and may increase the risk of adverse postvaccination events.” The AVMA recommends that vets create “core” and “non-core” vaccination programs, and that schedules be customized to fit the needs of each individual animal. The core program of most vital shots would protect against rabies, parvovirus, adenovirus, hepatitis, and distemper. The non-core program targets diseases that are of limited risk in the region where you live or that pose less of a threat to the dog because of lifestyle.

Note that none of these authorities recommends discontinuing vaccinations altogether. Vaccines remain our first line of defense against dread diseases that can be fatal to a dog. However, especially in the case of small-and toy-breed dogs, the practice of giving multiple vaccines in one shot and automatic yearly boosters is a matter of grave concern. These smaller canines have had more adverse reactions than their larger counterparts, and yet they are given the same dosage that Great Danes receive. Some breeders now advise against combination shots for small dogs, citing reactions ranging from fever, extreme exhaustion, and allergic reaction to anaphylactic shock. If you follow this dictum and ask your vet to rotate individual vaccines (rather than bundling them into one shot), be aware that this means more trips to the vet and increased out-of-pocket costs for you.

Many breeders now recommend that vets takes a titer, a blood test to determine a dog's immunity against a particular disease before administering the vaccination. This involves another expense as well. Your small dog's health is, of course, your first consideration — all the more reason why it's imperative to discuss the matter with your vet before choosing a course of action.

Denise Trapani, DVM, of The Animal Health Center in Walpole, Massachusetts, follows a core protocol for puppies. She administers three shots at eight, twelve, and sixteen weeks of age, from such diseases as parvovirus, adenovirus 2, parainfluenza, and distemper. “I don't automatically give the leptospirosis vaccine, especially to small dogs, because they tend to have more reactions to it,” she says. “I will only do it if they are at risk.”

Not all experts feel the same, as reflected in the view of Dr. Leanne Bertani. Writing on vaccines for Cavaliers Online, the newsletter for fanciers of the cavalier King Charles spaniel, Dr. Bertani states, “Leptospirosis is an important disease because it can be transmitted to man and some other animals, and can cause severe kidney disease.” She adds that “it is one of the vaccines most likely to cause a fatal anaphylaxis in puppies.” Similarly, she recommends vaccinations against coronavirus, bordetella, giardia, and Lyme disease only on a case-by-case basis. Again, as a small dog owner, you need to assess your own pet's risk when you plan its vaccination program.

Rabies is a different matter. Rabies is a viral disease affecting the central nervous system, transmitted by contact with the saliva of an infected animal. Once the symptoms appear, it is almost always fatal. This is why you should not let your dog come in contact with wildlife. Your dog's outdoor play should always be supervised. Any sightings of wild animals acting unusually aggressive or moving with a staggering gait should immediately be reported to your local animal control officer.

Rabies is on the rise among wildlife in the United States and is transmittable to humans as well. Vaccinated dogs and cats serve as buffers between us and infected wild animals. Raccoon, skunks, coyotes, foxes, wood-chucks, bats, and some farm animals are most susceptible to getting rabies. Each state requires rabies vaccination, but the schedule varies from state to state. The first rabies shot is usually given at sixteen weeks of age.