This practice of vaccinating animals upon arrival is not "thoughtful" medicine IMHO. These poor dears do arrive stressed and probably a lot of them poorly nourished and to vaccinate them further suppresses their immune system, for probably about 10 days, actually making them more susceptible to opportunistic organisms. Furthermore, it takes at least 7 days for their bodies to respond to the vaccine.
The homeopathic "nosodes" for kennel cough has been shown experimentally to confer a better level of protection than the conventional vaccines do - for a good discussion on vaccines see, "Homeopathic Care for Cats and Dogs", Dr. D. Hamilton. I don't believe there is any evidence that distemper or parvo nosodes are effective at preventing those respective diseases and I wouldn't suggest using those in any shelter situation. Most adult animals do not need vaccinating and all that vaccinating them during a time of stress will do is make them more susceptible to other bacteria/viruses.
In Calgary I consulted for a large pet store chain that retailed a lot of puppies and kittens. They experienced a lot of vomiting/diarrhea and other health problems in the young ones shortly after they arrived which they had been in the habit of treating with antibiotics. I instituted a program of feeding a probiotic (Wysong's Pet Inoculant) and using Wysong's Biotic powders and the results were terrific. I also had them hold off on vaccinations until the newly arrived had had a chance to acclimatize to their new housing.
Richard Calland,
Granville Island Vet Hospital
Vancouver