Expert: Terry B - 4/17/2007

Question
My partner admitted he had unprotected sex on holiday 10 days ago  although he entered her he says he withdrew before completing the act, but he had since had  unprotected sex with me.  Although he has no symptons I know both of us will need to take a test in 3 months to be completely sure, but is AIds immediately infectious or is there a period when it is less likely?

Answer
Dear Alex:

Peace.  I applaud your partner's honesty in informing you of his (and your) possible risk.  The good news is that one exposure does not necessarily lead to an infection; the potentially troubling news has to do with what happens if an infection does occur.

When a person is infected with HIV, the virus enters a cell, breaking apart the genetic information inside that cell to make more copies of HIV.  This process continues within the cell until so many copies are made that the cell ruptures, releasing more copies into the bloodstream.  This continues, producing more and more copies of the virus at an exponential rate.  As the virus invades more cells it enters the lymph nodes and bone marrow, insinuating itself in parts of the body where blood and immune cells are produced.  This is why it is so hard to destroy HIV once an infection has begun (and why finding a "cure" is so difficult.

HIV does trigger a response from the immune system and the creation of cells and antibodies to suppress HIV, but it takes some time before this happens, and suppression is always incomplete.  

Therefore, the amount (concentration) of HIV in blood, semen, vaginal secretions, and breast milk is highest at the time of initial infection and late in the disease when the immune system can no longer provide suppression.  This means, unfortunately, that a person is most able to infect another prior to producing antibodies (immediately after infection), or in late stage HIV disease.

Please be tested and in the meantime protect yourself and your partner from potential re-infection.  HIV mutates (makes slightly variant copies of itself) at high rates; the variations further burden the immune system (hastening progress to illness) and can result in resistance to available medications.

Sincerely,

Terry B