Puppy Shots: Vaccination Issues for Breeders
By Christie Keith

This article is meant to inform you of research, opinions, and personal refelections that might be useful to you in determining a disease prevention program for your pet. It is educational in nature, and is not intended as veterinary advice. The author cannot be held responsible for any unfavorable results from the use of this information. Readers should seek professional veterinary advice for any health decisions involving their pets.

Most breeders, even those who don’t like vaccines and don’t use them on their adult dogs, do give at least some vaccinations to their puppies. They are looking for a vaccination program that is as safe and effective as possible.

My main focus here is on vaccination for canine parvovirus and canine distemper. For my thoughts on other vaccinations, please read Re-vaccination: Vaccination for Previously Vaccinated Dogs and Older Puppies.

Conventional vaccine protocols are designed to give multiple vaccinations to puppies a few weeks apart. Most people and even many veterinarians believe that more than one vaccine is needed to “prime” the immune system or build immunity, but in the case of modified live virus vaccines for parvo and distemper, this isn’t really necessary.

We don’t repeat vaccinations for parvo and distemper because we need vaccines more than once to form immunity. They are repeated for two basic reasons only: Habit, and to catch those few individuals who for some reason don’t respond to the first vaccination. A single immunizing dose of a modified live virus vaccine – in other words, one vaccine that works – will form long term, probably lifetime, immunity to parvo and distemper. (Kirk’s Current Veterinary Therapy XIII; 2000; “Vaccines and Vaccinations: Issue for the 21st Century”, Richard B. Ford and Ronald D. Schultz; (Kirk’s Current Veterinary Therapy XI, “Canine and Feline Vaccines,” Phipps, Schultz; R.D. Schultz, “Considerations in Designing Effective and Safe Vaccination Programs for Dogs,” May 2000; Schultz, “Duration of Immunity to Canine Vaccines: What We Know and Don’t Know.”)

We don’t need to keep repeating the vaccines to know if they worked, either. Although titers as a measure of ongoing immunity aren’t all that useful, as a measure of whether or not an animal formed immunity from a recent vaccination, they are very reliable. (“Vaccines and Vaccinations: Issue for the 21st Century”, Richard B. Ford and Ronald D. Schultz. Kirk’s Current Veterinary Therapy XIII, 2000.) Since it takes 7-10 days for the immunity to form, if you test titers ten days after a parvo and/or distemper vaccine, you will know if the puppy had an immunizing response. You don’t need to guess.

If your puppy already seroconverted due to the vaccines he or she already was given, there is no reason or benefit to repeat them. She’s already immune, and she won’t get “more immune.” There is no “booster” effect, because the antibodies from the first vaccine will wipe out the vaccine virus, just like maternal antibody does. (Schultz, R.D., “Current and Future Canine and Feline Vaccination Programs.” Vet Med 3: No. 3, 233-254, 1998.)

What If They Don’t Form Immunity?
Some puppies will be given a vaccination and not form immunity (seroconvert). This can be due to improper vaccine storage or administration, but it’s usually due to improper timing of the vaccine. Puppies get antibodies (passive immunity) from their mothers in the two days after birth, from the colustrum. If you vaccinate a puppy at a time when maternal antibody levels are high, those antibodies can prevent the virus in the vaccine from triggering immunity in the puppy. It’s possible for a pup to have enough maternal antibody to inactivate the parvo vaccine, but not enough to protect from disease.

The answer is not to vaccinate earlier or more frequently, but to vaccinate scientifically. Earlier vaccination is clearly a doomed strategy, because maternal antibody wears off over time, and the puppy would have had more, not less, maternal antibody at a younger age. More frequent vaccination will often make the problem worse, as well, because it takes up to two weeks for immunity form after a vaccination is given; it’s not instantaneous. If another vaccine, even for a different virus, is given during the two week period following a vaccination, it can interfere with the immunity from the first vaccine as well as the second. Waiting a bare minimum of two weeks between vaccinations is an immunological requirement. Three is better.

This problem is actually less critical than it was in the past. In the early 90s, Dr. Ronald Schultz did a study showing that some available canine parvovirus vaccines were not providing protection even when given according to label directions. Since then, nearly all approved canine parvovirus vaccines have been reformulated to break through resistance from maternal antibodies, and provide immunity at a much younger age, so this problem is less common now. These are called “high titer” vaccines.

Other causes for non-conversion include improper vaccine shipping, storage, or handling, using a low quality vaccine, or immune problems in the puppy. Most of the time when dogs get a disease shortly after vaccination, it’s because the dog encounters the pathogen in a vet’s office, a vaccine clinic, or a shelter. It is not a case of primary vaccination failure. It is a case of the dog not being immunized at all at the time they encounter the virus. However, while extremely rare, it’s not completely unknown for modified live viruses to “revert to virulence” and become able to cause the very disease they were given to prevent. In order to determine if this happened, have your veterinarian order a DNA test on your puppy’s virus, to see if it’s the “wild” parvovirus, or the vaccine strain. If it is the vaccine strain, the vaccine manufacturer should be reported and should be liable for all your veterinary bills as well. Contact an attorney for more information. I should stress again that this rarely happens.

What Protocol to Use
I can’t tell you what protocol to use. If you want my personal opinion, I believe that protocol “A” from Dr. Ronald D. Schultz of the University of Wisconsin School of Veterinary Medicine seems like the safest mainstream protocol I have seen. You can review it in his article Considerations in Designing Effective and Safe Vaccination Programs for Dogs.

Dr. Schultz does recommend giving Canine Adenovirus-2 (Canine Infectious Hepatitis)and an initial rabies vaccination, as well as parvo and distemper, at age 12-14 weeks. Since he himself says that there have been no cases of Canine Infectious Heptatis in the United States in over 20 years, I don’t quite understand why he includes this vaccine. It is not available by itself, and has been shown to cause immune suppression when given in combination with Canine Distemper (Kirk’s Current Veterinary Therapy XI, “Canine and Feline Vaccines,” Philips, Schultz), so I would consider not giving it. (Rabies is governed by laws, not science, so I really have no comment on this other than to recommend giving rabies vaccine by itself, at least two weeks before and/or after any other vaccines.)

I would also prefer to give parvo and distemper separately. If you do that, though, the question is, which do you give first? There is a good argument to be made that distemper is easier to vaccinate for at a younger age, as maternal antibody is almost always gone by 8 weeks. However, parvo is much more common than distemper, and the younger the puppy is when he or she gets it, the worse the outcome is likely to be. My own choice would be to give parvo first, but it’s an individual decision. Giving the two in combination is also a reasonable choice, although not one I would make.

I get a lot of mail asking where single parvo and single distemper, or a parvo/distemper combination, can be obtained. Schering-Plough makes the “Galaxy-D” single distemper vaccine; Intervet (Proguard) and Duramune both make single Parvo vaccines, and Intervet (Proguard) also makes a combined parvo/distemper “puppy” shot; if your vet won’t order them for you, you can buy them online at http://www.revivalanimal.com/. I have no commercial interest in any of these companies nor any experience purchasing anything from them or using their products; they are simply resources for single-antigen vaccines of which I’ve been made aware. Use at your own risk.

I would also suggest that instead of guessing when maternal antibody is gone, you can increase the chances of vaccine success for parvo by doing a simple blood test for maternal antibody. That way you can give the parvo vaccine at the moment when you know the maternal antibodies are really gone, and can be sure it’s going to work.

Most breeders don’t want to wait that long, and instead rely on the “high titer” vaccines such as Intervet’s Proguard, which was designed to overcome maternal antibodies. (Note: As of August 2007, most approved parvo vaccines are now considered “high titer” vaccines.)

How Do I Know It Worked?
Whether you give the high titer vaccine, a regular parvo vaccine, or do the maternal antibody test, you can then wait ten days after giving the vaccination and run a parvo titer to see if they seroconverted. If they did, and you gave only the parvo shot, you can now give a distemper vaccination. Wait two weeks, and you can check the distemper titer, too.

If the puppy had an immunizing response to the vaccines, then it just doesn’t get any better than that, as far as vaccinating for parvo or distemper goes. That is the brass ring and your puppy got it.

If you are nervous you can do a parvo/distemper titer at one year of age, but the correlation between post-vaccine sero-conversion to these two diseases, and protection from the disease throughout the dog’s life, is extremely high. Parvo and distemper are almost unheard of in vaccinated adult dogs, or adult dogs, period. (Kirk’s Current Veterinary Therapy XIII, 2000; “Vaccines and Vaccinations: Issue for the 21st Century”, Richard B. Ford and Ronald D. Schultz.)

Are You Still Not Sure?
What vaccination protocol to use is a highly personal decision. Most vaccine protocols are “one size fits all,” and based on “just in case” and guessing. If you make the decision to give puppy shots, then design a vaccination program based on science and reason, not superstition, fear, habit, and marketing strategies.