Please make sure your puppy gets his/her puppy vaccines. They can get really sick without them. The reason most puppies don't get certain diseases is because they get vaccinated, don't get complacent and think that those diseases aren't still out there.
That being said, once your puppy is a over a year old, you could talk to your vet about doing titres to minimize vaccines. They are quite costly, but if its something you are worried about, it is definitely a good option for you.