Welcome to JustAnswer! I am a licensed veterinarian and would be glad to help!
The snake(Bite) vaccines can be effective, but this is not a 100% treatment without any other therapy.
When bitten, treatment and care is recommended immediatly.
The vaccines are specific to a certain type of snake venom and not all inclusive for every snake venom out there.
For example, if the dog is bitten by a copperhead, yet vaccinated for a rattlesnake - the vaccine is not effective.
Side effects -similar to any other vaccine, such as rabies
- Hypersensitivity, allergies, hives, etc.
The snake bite kits - not much value in those.
That is my impression from seeing these in the ER.