Food for thought:
A Science-Based Vaccination Schedule For Your Dog And Cat
Giving a dog Benadryl and Metcam will make him comfortable after a vaccine. But the dog’s body is trying to tell you something, depending on his post vaccine symptoms. More severe symptoms should not be ignored, and IMHO a less frequent vaccine schedule would be discussed with my vet. Lyme vaccine only works 60-70% of the time, and there are topical tick repellants that can be used if you decide not to vaccinate.
I think the Flu vaccine helps to lessen the severity of the disease, but does not prevent a dog from acquiring the disease. With dogs that have problems getting vaccines, I would skip this one too and keep the dog in the house, or at least away from other dogs and areas that other dogs frequent a lot.