Are you serious?!

I wonder about a dog that already has a weak immune system? Like what it does to them.
I just wanted to clarify that this disease of lysing the red blood cells is known as IMHA or immune mediated hemolytic anemia. This basically refers to a disease where the immune system goes haywire and starts to respond to its red blood cells as if it were a foreign invasion there for "hemolyzing" (destroying) the RBCs.
IMHA as far as a vaccine reaction is goes is EXTREMELY rare. I lost my sheltie puppy to this reaction after a battle with parvo and am still doing research as far as to why my conclusions are interesting but definately off-topic here.
As far as my opinion on vaccinations...I work as an ER technician and am going to school to become a veterinarian myself. I believe your most important vaccines are from 8wks to 16 wks and 21 wks in specific breeds. The reason for all these boosters lies in the fact that puppies that come from well-vaccinated mothers end up with an increased amount of antibodies that pass through the placenta, and are also given in the colostrum during the first few hours after birth.
These antibodies serve as a passive secondary immune protection meaning that they will protect the puppy well, but in the long run because they are "passive" they will not stimulate the creation of antibodies for the puppy. when these antibodies from the mother are gone so is the protection. So, the theory here is that when we vaccinate the first 8 weeks we probably still have a certain number of mom's anitbodies negating the vaccines effects, but as we continue to vaccinate we are getting less of mom's antibodies and more of puppy's.
Next reason for boosters lies with the fact that the first time a puppy's immune system sees a disease the first responders come out which basically will try to kill everything by phagocytosis without creating any type of real memory. What we want to happen is antigens to be taken and analyzed by the secondary immune responders so that the next time the puppy's immune system comes into contact with the disease more specialized immune cells take over due to familarity with the antigen. So we booster to familiarize the puppy's secondary immune response system with the disease as much as possible.
This being said I'm completely and utterly against vaccinating sick puppies and kittens. At my clinic if a puppy shows signs of sickness we will NOT administer any vaccination.
As far as lepto...I do vaccinate for it, I'm also very much into hiking and live in an area where I see about 1 lepto case a week and at least 1 dog positive for the disease a month it is a nasty disease and I would not want to see my dog exposed to it. They also have a higher risk because of where I work so I vaccinate on a 3 year rotation for DA2PP and Rabies. Lepto I give bi-annually as well as bordetella just because my pup (when I had a pup) comes to work with me and is exposed to many different types of upper respitory diseases. (The joys of being a veterinary medical staff's dog eh?)
Anyway I apologize for the long post, I just have been through the ringer on this one and feel very strongly about this subject.