1. Even though their tests do not show a presence of HIV in his system, doesn't mean it's not there. This virus is known for hiding well and popping up later. It's been seen before in patients taking anti-retroviral drugs. It is possible that if more sophisticated tests were used on this patient, they would detect the virus that is still in his body. So it's still not entirely clear that he is HIV-free.
2. The chances of finding a bone marrow donor with two copies of this genetic mutation for everyone one of the 33 million people worldwide living with HIV or AIDS is not realistic because only one percent of Caucasians and zero percent of African Americans or Asians have this particular genetic mutation.
3. Bone marrow transplants are dangerous for patients.
4. Bone marrow transplants are very expensive and not an option for many people living with this disease around the world.
Both the doctors in Berlin and AIDS experts we've spoken with say this is a "proof of principle." "It's an interesting case for researchers," according to Dr. Rudolf Tauber