Hi Dr. Barchas,
A vaccine against rattlesnake bites is available for dogs. The vaccine protects primarily against the Western Diamondback rattlesnake (the most dangerous species), although it provides some degree of protection against a number of other rattlesnake species. The vaccine does not offer protection against other types of snakes, such as coral snakes.
The poison in rattlesnake venom is a protein, and the vaccine causes the dog to create antibodies to the protein. The antibodies act to disable the poisonous protein after a snakebite, reducing its toxicity. This type of vaccine is similar to a human tetanus vaccine. So, although snakebite is not a disease, the technique used to vaccinate against it is not new.
It’s important to remember that the vaccine does not offer complete protection against rattlesnake bites. Even in vaccinated dogs, any snakebite should be treated as a medical emergency.
Regarding the availability of a rattlesnake vaccine for cats, the manufacturer claims that the vaccine appears to be at least as effective in cats as in dogs. However, it is not yet licensed for cats, and its safety in felines is not known. My guess is that the company licensed the vaccine for dogs first because they are much more likely than cats to stick their nose in a rattlesnake’s face.