Hi Jeanette2 -
You have hit on one of the fairly contraversial topics in veterinary medicine - For many years, the distemper/parvo vaccine was recommended to be given yearly as that is what the companies that produce the vaccine recommended - they tested the vaccine after one year and found it to be effective at that time frame, but they did not test the vaccine to see if it lasts longer than a year. Now, independent studies have been done and they show that the vaccines last considerably longer than one year in adult dogs. The vaccine is still only labeled for one year, and that is still what many vets recommend, but the thoughts on this are changing because we also worry that over-vaccinating is not good for the pets either.
Puppies still need to go through a series of vaccines, beginning at 6 - 8 weeks of age and repeating every 3 - 4 weeks, until they are approximately 15 - 16 weeks of age. Certain breeds that are more susceptible to parvo we may continue boosters until age 20 or so, but Shitzus are not not one of these susceptible breeds. Then, they will be good for one year. At one year of age (actually approx 1 year and 4 months) , they should receive a booster that will last one year again. After another year (age is now 2 years and 4 months) another distemper/parvo booster can be and and it would be reasonalbe to expect that this vaccine would last longer than 1 year - some will say go every other year or every third year from here on out for distemper/parvo booster.
Now the petstore vet is probably not going to agree with this as they are in the business of selling vaccines and the vaccine is still only labeled for one year, but the studies have shown that the recommendations I gave above provides excellent protection.
Rabies is a bit different in that there are different types of vaccines available and some are labeled for 1 year while others are labeled for 3 years. Also, since Rabies is a disease that is transmissible to humans, there are actually laws that govern the protocol used for rabies vaccine. Unfortunatley, these laws vary from state to state and sometimes from town to town within a state, so you need to follow whatever the law is in your community. You can call different clinics in the area and ask them that question to find out what the law is in your area.
There are other vaccines that dogs get, depending on their lifestyle - Bordatella (kennel cough), Lyme, Leptospira, Giardia - if you need more information about these vaccines, just let me know.
I hope this answers your question. If so, please click Accept. If you need more information, please let me know.