Letter: coronavirus and pets

Early in the onset of the Covid 19 pandemic, I read that dogs and cats are common carriers of various coronaviruses. As a healthcare provider and dog owner, I was concerned about the implications this might have for my family and millions of pet owners. This information posed many questions: Are these animals susceptible to harboring Covid 19 virus? Can they be infected by it? Can they spread it to humans? If not, why not? Is the human immune system invigorated against coronavirus by constant exposure to household pets? Does this translate into decreased susceptibility to Covid 19? Are any researchers comparing the frequency/severity of Covid 19 infections in pet owners vs. non-owners? I doubt if any one person has definitive answers to all these questions. Veterinarians, virologists and epidemiologists could provide pieces of knowledge to this puzzle. I would appreciate a response from any of you with special knowledge that could help create a clearer picture of these issues before another viral epidemic comes along.