"new" lyme shot?
we use merial's recombitek lyme vaccine where i work. we see a significant amount of lyme disease (in dogs and humans) in this area, and it's dramatically on the rise. five years ago, the clinic where i worked very very rarely recommended the vaccine. now we see so much lyme, we recommend it to many of our clients if they live in areas where there's a big tick problem.
really, it's all based on what your dog's risk is. if you live in an area where lyme is a problem and you see ticks on your dog regularly, it might be worth considering. if you live in an area where lyme is a problem but your dog lives a lifestyle in which he doesn't pick up ticks, then i'd just use frontline.
a lot of dogs are infected with lyme but don't get sick from it. we see quite a few dogs come up lyme positive on 3DX snap tests when what we're looking for is heartworm. dogs who do get sick from it usually recover without a whole lot of trouble, though there are some cases where it affects the heart or kidneys and is a very very serious thing indeed.