Has your dog's personality ever been affected by a booster shot ...?

I wouldn't lose sleep over it, as you said his behavior is the same, and behavior is one of the first clues that something is wrong with dogs. I always knew my dogs were sick because they go off their food, eat grass, not as playful, etc. but as you're probably already doing, continue to keep a close eye on him because, I've never owned a Chihuahua, but that noise doesn't sound too normal.

I mostly have had big dogs, but I had an 8lb toy poodle for many years and there were times after shots he was out of sorts for up to a week after it, my big dogs like my Mastiff and my Chow mix were ALWAYS fine, I think shots affect the little guys a lot more strongly. you haven't had an answer from the vet, but owners know their dogs best, so if he's not back in his best condition by, say the weekend, or Monday, take him back to the vet and insist he get looked at, or that you at least get an expert's opinion before his next round of shots.

Maybe he has a bit of a cold? Or maybe he's having a bit of a reaction to the booster, you know, like people can sometimes. Unless anything changes drastically, I would wait until the next booster, since it's only a week away, to ask your vet about it. Just keep an eye on him.

Hopefully he gets better!

If you trust your vet then discuss your concerns with him/her. A serologic titer test is an excellent idea too. The antibodies given in vaccines do not magically evaporate after 365 days. The sad truth is that booster shots are the bread and butter of veterinary medicine and in spite of overwhelming evidence showing that overvaccination is not helpful and in fact can be harmful, many keep pushing the "annual booster" regime.

You sound like quite a worryier....

but

your dog may be really sensitive and responsive to the vaccine and you can ask your vet if he can give the dog a slightly reduced amount of the vaccine. Some children and dogs respond strongly to vaccination and need slightly reduced dosages.

A few months ago my 12 year old Akita had a bad reaction to rabies shot. She had a seizure and could hardly walk for a few days.

Make sure you tell your vet! My dog is allergic to some shots. They can give them something before.

yes, it is called vaccinosis, and it is a very common thing, but since vets make money off vaccinations, they tell us to not worry, and they continue business as usual.

report this reaction, and do not continue the vaccinations, unless you want to risk your pets life.

http://www.leerburg.com/vaccinosis.htm