A. M. Carter in Medium:
I had a bone marrow transplant in 2017. Most people don’t really know what that is. In the simplest possible terms, it means that my doctors gave me a new immune system, by replacing my sick bone marrow with healthy bone marrow from my sister.
The transplant process is basically a blood transfusion, but instead of blood cells, I received new immune cells from the bone marrow, which then took over my body and made it their new home, thus giving me a new immune system that worked normally.
In order for the transplant to work, I had intensive chemotherapy to kill off my original defective immune cells. For a month before and for many months after my transplant (until the new immune cells fully took over), I did not have a functioning immune system. This means I was vulnerable to EVERYTHING.
Many transplant patients get weird infections that most people have never heard of. Many common viruses, that healthy people easily clear without a single symptom, become deadly in a person with no immune system to fight them.