My dog is in contact with other dogs, I take him to pet stores, he goes to dog parks sometimes, we go out a lot in public, he is outdoors all the time, in woods, etc, and I still feel perfectly safe with the vaccines he's been given and am not worried one bit.
The Lyme vaccine is kind of a joke IMO. Lyme tests are so inadequate in being able to help determine a definitive diagnosis anyway, so many false-positives and only 5% of dogs show symptoms. My Jackson was one of the 5%, he came up lame one day on his back leg, thought it was odd, did x-rays, etc, it ended up being a positive lymes test. With a few days worth of pain meds and doxycycline, he was 100% better the next day. For the past 3 years, his lyme test has come back negative and he's never had any other symptoms. Whether he's actually negative or not, who knows, but I still wouldn't touch the lyme vaccine with a ten-foot pole.
Lyme vaccines were removed from the human market because they failed to perform the proper safety studies prior to release and because of the numerous adverse events that followed the vaccine, some resulting even in death. There are other tick borne illnesses that are much more serious than Lyme, and we have no vaccines for them. So even if a very safe and effective Lyme vaccine came out, having your dog vaccinated for Lyme isn't going to lessen the need for tick prevention. And for humans, it's a worse disease than for dogs. Rarely is it as serious for a dog to have lymes as a human.
Reasons not to give it:
Revaccination
Lepto is another one. Lepto is really very rare, in the big spectrum of things. Less than 200 cases in the U.S. and half those in Hawaii. It's really common in tropical countries with heavy rainfall. The vaccine doesn't even protect against all the different strains of the lepto. Vets see more cases of reactions to lepto vaccine, than lepto itself.
Either way, I can't give lepto vaccine even if I wanted to (horrid reaction to it).