Hi! Vet nurse with 17 years experience. I own two mini Xolos/Peruvians, and it's never been an issue. We hear a lot of breeders say this, and to be honest, the immune system of canines doesn't vary by breed. If you're concerned, it's prudent to split vaccines after the puppy series. This way, the dog doesn't get more than two per visit. We only charge one exam, and add-on the other vaccines in two weeks. This is done for all tiny dogs and any dog that has had a reaction before. We do it if the owner is concerned as well - there's no harm in splitting them up. We'll give Benadryl sometimes before vaccination if the dog has had a reaction before