Canine Parvovirus Explained – Dogs Who Don’t Respond to the Vaccine
One in 1,000 dogs will never develop immunity to canine parvovirus no matter how many times they are vaccinated against the disease. When parvo first roared onto the canine scene in the 1970s, these genetic “non-responders” (as they are called) came primarily from certain breeds. Today, you’ll find non-responders in dogs of all shapes, sizes, and breeds. Keep reading to learn more …
In the early days of canine parvovirus, most vaccine non-responders were dobermans or rottweilers.
“We lost of a lot of puppies of those two breeds because genetically they were incapable of responding [to the vaccine],” says Dr. Ron Schultz at the University of Wisconsin veterinary school. “Today, we don’t see any greater number of non-responders in those two breeds because they all got wiped out. The genetics were wiped out, so today, we see non-responders in all breeds, but not like we saw in those rottweilers and dobermans early on. And, it’s not surprising it’s those two breeds because they are closely associated breeds. Of course, the genetics were there that were perpetuated without any adverse events until parvo came into the world, which was really in 1978.”
So, if you ever hear of an adult dog who has been vaccinated for parvo, who gets parvo or dies from parvo, then that dog is probably the 1 in 1,000 non-responder. He will be at risk from parvo his whole life.
There is another way that a seemingly vaccinated dog could get sick or die from parvo, and that’s if it is a young adult vaccinated dog who has NOT yet had his 1-year booster vaccines. Remember how we talked last week about maternal antibodies blocking the parvo vaccine from working?
Well, a young dog that was vaccinated (even several times) might not have developed immunity because of high level of maternal antibodies during vaccination … that have now gone away.
That’s why veterinarians like to re-vaccinate puppies at 1 year of age. Just to be extra sure that immunity has been established.
It’s also why it’s a good idea to have a puppy titer tested 2-4 weeks after you finish the vaccines you’ve given — to make SURE the vaccines actually induced immunity. No more assuming or guessing.
If the puppy doesn’t show any parvo titers, Dr. Schultz recommends re-vaccinating and re-checking titers on puppies. If the titer test still comes back negative, long after maternal antibodies are gone, then you have yourself a non-responder.
So if you ever hear reports about adult / vaccinated dogs with parvo … I want you to think non-responder or blocked response first … NOT that the vaccine no longer works or that there is a new strain of parvo out there.
I have one more parvo post I want to write about really neat ways veterinarians can figure out exactly when to give a litter of puppies vaccines so that they work best — which means they can give them fewer times and still provide good protection. Stay tuned for that!