As winter approaches, a spike in human infectious respiratory illness is anticipated, including COVID-19. Many dog owners worry that if they contract the COVID-19 virus, can they give it to their dogs and how would they know if a dog has COVID. It’s not an easy question to answer, and research is a bit inconclusive and conflicting on some things.
While science has not yet confirmed canine COVID transfers, the Centers for Disease Control and Prevention suggests caution, saying, “If you are sick with COVID-19 (either suspected or confirmed by a test), you should avoid contact with your pets and other animals, just as you would with people. Contact includes petting, snuggling, kissing, licking, sharing food, and sleeping in the same bed.” (See sidebar for symptoms.) Basically, the CDC is suggesting we play it safe.
What We Know About Canine COVID
There’s a lot scientifically unknown about dogs and COVID, including that we do not know for certain that ALL dogs exposed to the virus get ill from COVID-19. Most do not appear to be sick. If the dog does get ill, it is rare, mild, and self-limiting. Side note: Cats and ferrets are different in that they can show signs of illness.
We do know that dogs develop neutralizing antibodies to COVID-19. This means that the canine immune system can recognize a COVID-19 virus as foreign and can mount an antibody response to fight the virus. While there are some diagnostic laboratories set up for COVID testing in animals with known exposure, since it is unlikely for dogs to infect people, this might not be necessary.
Dogs are thought not to shed the virus for a prolonged period, even if they test positive for antibodies to the virus. Research indicates that there is a narrow window of time in which samples can be taken for accurate testing, with confirmation of infection coming from serologic antibody testing. This makes the likelihood that dogs could transmit COVID-19 to a person low.
Care should still be taken handling the pets of infected owners because their coat could still contain infective viral particles shed by the owners, though the risk is much smaller than interacting with the actual sick owner. If a healthy person needs to handle the pet of a currently infected owner, handwashing afterward is a sensible precaution.
The serologic antibody testing in dogs has shown rates of infection of greater than 40% in infected households (Stevanovic 2021, Hamer 2021, Bienzle et al 2022). Testing of random populations of dogs show a low rate of antibody detected (0.2% to 3.4%). The random population could include leftover canine blood samples submitted to the lab for other testing. It is not likely to exclude dogs from households with a history of infection (Ito et al 2021, Patterson 2020, Smith 2021).
There is no vaccination for dogs against the COVID-19 virus. Since most dogs who are exposed do not get sick, it is unlikely that a canine vaccine will be developed.
As a final note, we do know that scent dogs can detect the virus in humans and have been considered for screening.