Vaccines: Core Vs. Controversy

Vaccinating your dog is what most people might term a “no-brainer,” but as vaccine science has broadened, it pays to be knowledgeable. In the 1970s, only a few vaccines were available for pets, and by the 1980s, there were 12 or 14, and now there are even more variables, from the “5-way” combination of core vaccines to the 7- or even 10-way cocktails of core and non-core vaccines. (“Core” refers to the distemper, parvo, adenovirus and parainfluenza virus vaccines, commonly known as “DAPP” and given as a combination, along with the rabies vaccine.) These are serious, life-threatening diseases that all puppies should be vaccinated against early in life. All other vaccines, such as bordetella, leptospirosis, canine influenza and Lyme, are considered “Non-Core” and optional. Some of these non-core vaccines can also be directed to bacterial infections, versus viral. (And if that’s not enough, there’s even a vaccine for “Crotalus atrox,” Western Diamondback Rattlesnake, for dogs with a defined risk for exposure.)

Live vs. Killed

Not only are there more vaccines, some vaccines are available in more than one form. Ask your vet to advise you on the risks of using killed (which uses an inactive form with all the infectious bacteria taken out and killed, along with an adjuvant to stimulate immune response) versus modified live vaccines (a weakened version of the virus), versus recombinant (which uses only a specific piece of an infectious organism like a protein or a sugar to produce a very strong immune response) for your particular pet. The bordetella and parainfluenza combination for kennel cough comes as an intranasal vaccine; the bordetella-only vaccination (without parainfluenza) comes in injection, intranasal and oral versions. The distemper vaccine comes in modified live or recombinant versions, while the rabies vaccine in the U.S. is always killed virus. Canine influenza and leptospirosis vaccines are only available in killed versions. (An advantage of killed virus is that the animal won’t shed the virus, which could possibly be transmitted to another unvaccinated animal.) The Lyme vaccine is available in four different versions, from two types of killed to recombinant to chimeric-recombinant, but isn’t effective against other tick-borne diseases.

Pros and Cons

While the core vaccines are without question essential for the health and safety of your pet, like with children, vaccines are not without risk of side effects. Pregnant dogs or those with compromised immune systems are often prohibited from receiving certain vaccines. Dogs can have a reaction to vaccines, which can be caused by the antibodies or to one of many other ingredients, such as chemicals and heavy metals. Most reactions are usually temporary, such as lethargy and soreness.  But more serious allergic reactions, termed “vaccinosis,” even life-threatening anaphylaxis, have occurred with some vaccines, and can be more chronic, taking time to develop. Many holistic practitioners use an anti-vaccinosis homeopathic to reduce some of the side effects.  These reactions, along with theories about how over-vaccinating can impact the immune system, are the reasons that many owners choose to have serum antibody titers done in the years following the initial core vaccines. Dogs who are older, are immune-suppressed or certain small breeds, may require single vaccines, spaced four weeks apart (see or in the case of required rabies vaccination, given certificates from their vet saying that the animal may be at risk from further rabies vaccines.

Non-Core Not Necessary?

But with more “non-core” vaccines being promoted by vets, how do you decide which are best for your dog? For example, the canine coronavirus vaccine, which is not recommended by the American Animal Hospital Association because it causes mild or subclinical disease for a disease that usually occurs in dogs younger than six weeks old and is a self-limiting disease. The leptospirosis vaccine tends to have a higher rate of side effects, some of which are potentially very serious or fatal. However, the disease is considered “situational” and if it has become prevalent in your area, or you live in a hot, humid climate, or in a rural area where the exposure to rodents and animal farms, and thus the soil and water are more likely to be contaminated with the bacteria, it can be a good choice. While many of us live in areas with high tick populations, the Lyme vaccine only protects against certain variations of Lyme disease, and offers no protection against other tick-borne diseases such as ehrlichia and anaplasmosis, which we see much more of in rescue, and Rocky Mountain Spotted Fever, which has also popped up in the Northeast. Add to that, the risk of serious, debilitating side effects such as irreversible arthritis pain that mimics the symptoms of Lyme, and we have found that many Great Pyrenees and Pyr mixes are particularly sensitive to it. We have seen reactions as severe as debilitating lameness, heightened sensitivity and reactivity, even aggression in younger dogs, so we caution adopters about using this vaccine. Tick control methods such as topicals, collars (Seresto, Preventic) and even chewables such as NexGard are a must. Check your dog and yourself frequently for ticks and remove them (there are several very inexpensive tools available for this, aside from your trusty tweezers). Avoid tall grass or wooded areas where ticks love to hide. Keep your yard and trees trimmed so sunlight can reach the ground; there are even some other ways to control ticks, such as beneficial nematodes and diatomaceous earth, that are safe for children and pets.

In some cases, most dogs with strong immune systems are able to ward off certain viruses and we never even know they were exposed. Even so, commercial boarding or daycare facilities often require a bordetella vaccine. In addition, some facilities in high-risk areas require canine influenza virus vaccination, but the initial vaccination series must begin four weeks prior to entry into the facility. Vaccinated dogs can still become infected if exposed to the virus, develop some clinical signs and shed virulent virus.

With any non-core vaccine, your decision should be based on the level of risk and the amount of protection the vaccine can actually offer. Age, medical history, environment, travel habits, and lifestyle all should be considered and reviewed with your vet. Just because it’s available doesn’t mean it’s right for your dog.