A Holiday Course in Canine Immunology


‘Tis the season for new pets, dressed in bows, wriggling beneath the tree. And a perfect time for me to clear up some of the confusion that often accompanies them.


Did your new dog come “with shots”? It’s a serious mistake if you think this means she doesn’t need to see the vet. Puppy vaccinations are never finished until the age of 16-18 weeks. If your new dog is any younger than that, she needs to get to the doctor and finish up those shots. The most dreaded consequence of an “incomplete puppy series” (missed vaccinations) is parvovirus infection. Parvovirus is found nearly everywhere—indoors and out—and is very resistant to weather extremes. Once deposited, it can persist, and remain infectious, for years. There’s no way to avoid those parvovirus particles, since they are invisible to the naked eye and often left behind by perfectly healthy-appearing dogs. Take the necessary steps to protect your baby from this life-threatening disease, because the alternative is really a bad gamble.


Are vets trying to cheat you by insisting on a rigid series of inoculations for every puppy? Please allow me to explain the science behind the structure. Baby dogs come with a temporary supply of protective antibodies, generously supplied by their mothers. The stronger the mother’s immune system, the more protection will be conferred by these donated antibodies. In this way, virtually all pups are protected from parvovirus free of charge until the age of 12-14 weeks, when their borrowed immunity fades. Once that occurs, the pup is totally vulnerable, because the immune system of young dogs hasn’t got the necessary instructions for replenishing its antibody supply. Fear not: a properly prepared vaccine syringe contains complete, easy-to-follow instructions. They will be so clear that even a 3-month-old pointer can follow them.


It’s not quite that simple, though. Mothers tend to be very protective, and when they equip their offspring with a shield against disease, they are very serious about it. Those borrowed antibodies from Mother form an impenetrable wall that cannot be pierced even by the vaccine needle. Given too early, everything inside the syringe will be blocked by this protective barrier, so we want to administer our puppy vaccines at that critical moment when the wall is coming down. The timing is a bit different for every individual, so veterinarians had to develop a method for intervening at exactly the right instant. That’s how we came by our current approach, vaccinating every pup at regular intervals between the ages of 10 and 18 weeks. For decades, this approach has proved very successful in the prevention of serious viral disease.


What if you’ve already missed some or all of those puppy vaccines? Your dog is extremely vulnerable right now, but you can still catch up if you get him to the vet before he picks up something nasty. Don’t put it off; getting those inoculations on time might seem like a hassle, but it’s a walk in the park compared to being sick with parvo.


Dr. M.S. Regan