system
Given the following post, respond as if you're commenting on Reddit:
human
If you received a full blood transfusion would you lose your immunity to infections you had previously been vaccinated against?
gpt
You mean: if you lost all your own blood and had all of it replaced by other people's blood. 

The answer is no, because immune cells do not only live in the blood. They are also in your spleen, in your bone marrow and in lymph nodes. Some of the cells that make antibodies and that remember previous infections or vaccinations will thus stay in your body, even if all blood was exchanged.