Stem Cell scan be used for immunizing all humans against microorganisms such as Chikungunya, Chicken Pox, Hepatitis, Measles, Rabies and other bacteria and fungi.
We can take a stem cell/Haematopoietic cell from bone marrow from a person and induce immune response against all the infectious microorganisms in the laboratory and then again put it back in the body in the bone marrow or the lymphatic organs after creation of their immune response and such as all the B memory cell, T memory cell and other immune cells.
Such person will show immunity against all microorganisms whose immune induction is done. And for their lifetime be immune to the all microorganism diseases.
Also he/ she can be given vaccine of some recurring microorganism to boost immune response and to remain immune like Influenza Virus and Corona Virus.