Hi doc, I'm in dilema. My brother has 2 wives one is. One is HIVpositive another is negative. He is also negative. I am concerned about him becaus he insist on having live sex with the second wife who is HIV positive so that they can have a child.The first wife is barren. I feel he is risking his life and also risking the life of the first wife. He says that he has an unexplained immunity because he continues to test negative. I don't think it is true but he has convinced his two wives. So qtn is it possible to be immune to the drug. by the way he is blood group O

It is very rare, but it there is evidence that a very small subset of people have a genetic immunity to HIV. I believe it has to do with a defect in a gene called "CCR5." There may be other types of immunity, but it does not have anything to do with blood type (such as blood type O). I am not a doctor and this is not my area of expertise.

For most people having unprotected sex with an HIV+ person is risky for HIV transmission. That also means his HIV-negative partner would also be at risk if he were to become infected. And a person is usually highly infectious when they are first infected with HIV, before they develop antibodies (when their viral load is very high).

Thus, your concern is warranted. But again, it is possible that he does have a certain type of immunity. But as I said , this would be rare and would not simply be based on the fact that he has had unprotected sex and is not infected. This whole issue needs to be clarified by a physician who is an expert in this area.