There has been a vaccine for dogs and cats for a while now, not sure why it hasn't been released for humans yet. Lyme can be really horrible. Some people we know have a 30-something son who was very active (camping, hiking, rock climbing, etc.) until he was bitten by a tick. Now he's quadriplegic.

Typically because it's rare enough that the cost/side-effect risk of the vaccine isn't judged to be worth it.

Humans generally aren't vaccinated for Rabies either, unless you are e.g. a veterinarian who might have a higher chance of exposure to it.