Technically, a pet vaccine is feasible. In fact, several research teams say that they have already developed promising cat or dog vaccines; the shots that zoo animals are receiving were initially designed for dogs.

But vaccinating pets is simply not a priority, experts said. Although dogs and cats can catch the virus, a growing body of evidence suggests that Fluffy and Fido play little to no role in its spread — and rarely fall ill themselves.

“A vaccine is quite unlikely, I think, for dogs and cats,” Dr. Will Sander, a veterinarian at the University of Illinois Urbana-Champaign, said. “The risk of disease spread and illness in pets is so low that any vaccine would not be worth giving.”