I share your concern. Having looked at much research, we are not big believers in the safety or efficacy of vaccines either, but the Rabies is required by law. You can get the 3 year if your state allows it. The other thing I would suggest is to be sure to boost your dog's immune system prior and following the shot. Probably a good idea anyway given the dog's age. Probiotics are very helpful in supporting immune function in humans and dogs. Not sure about dogs, but in humans about 70% of your immune function comes from gut assisted lymphoid tissue. We have found dog probiotics to be more expensive than humans, so I just get quality ones for me and Buddy and I share.

Same with Omega 3's (aka fish oil). Buddy gets 1/2 tsp of mine which equates to ~800mg EPA/DHA a day. That's good for so many things (in humans and dogs) that it would require it's own thread to discuss.
Also, vitamins A, C & E are good for supporting immune function. Dr. Martin Goldstein, DVM, author of The Nature of Animal Healing: The Definitive Holistic medicine Guide to Caring for Your Dog and Cat, suggested the following program begining two to three weeks before vaccinations and extending two to three weeks thereafter:
Vitamin A - 10,000 IU a day for 50# dog
Vitamin E - 400 IU/day
Vitamin C - 2,000 mg/day (Start the C at 500 mg/day and increase every second day until recommended dose. Give the dosage in stages 2-3 times a day)
He also recommends a homeopathic remedy of thuja 30C after vaccinating.
Hope that's helpful. I wish state's would accept titers as proof of immunity, but that's not possible right now so we are either forced to vaccinate or break the law.
Sally