I am also really sorry this happened to Jack.
It sounds like it was a rare and fatal reaction to the shot, and not anything the vet did wrong.
Please accept my condolences on the loss of your dear little pup, Jack.
Hi. I worked with a vet for 8 years. What you describe is tragic, and very sad, and NOT your vet's fault (otherwise this would happen to alot more dogs). Of course the injection was given at low temperature: ALL canine and feline vaccines must be stored at 40 degrees F or lower until used. There is no way anyone could have predicted this happening to your dog. I'm SO sorry for your loss!
I am so sorry you lost your pup at such a young age.
Rabies shots can be given when the dog is 12 weeks of age. Here, different states can have different regulations. Rabies is required for all dogs as it is a fatal disease to animals and humans.
I don't know what you mean by a low temperature vaccine.
Often, especially in small breed dogs, vaccines are spaced out and not given together. Did your dog receive another vaccine at the same time?
Unfortunately, any dog can react to any vaccine just like people can have allergic reactions.
I know of dogs that don't feel well for a few days after a vaccine. I only know of one Yorkie that died after a Rabies vaccine.
If you have contact with the breeder you got the pup from, you might try contacting them to see if the parents or any other pups had reactions.
Wish I could be of more help.
So sorry you lost your pup.