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Ask the Experts


My wife is HIV positive and i am negative. She is on antiretroviral drugs and we have unprotected sex. If i were infected, would the virus have resistance to ARV if i were to start using?

Answered by: Robert Remien

Whenever an HIV-negative person engages in an unprotected sexual relationship with someone who is HIV-infected, there is always a chance that HIV might be transmitted to the negative partner. However, a lot is known about how the virus is transmitted and consistent and correct use of protective barriers can reduce the risk of transmission to a very minimal level. Further, proper adherence to HIV medications by a person with the virus can reduce her or his viral load to very low levels, even to the point of being undetectable by the test used. Even in this situation, however, the person remains HIV-infected and there remains viral replication, even when very low. Certain factors, such as a lapse in taking medications or the presence of a different infection, can cause significant fluctuations in viral load on a day-to-day basis. This means that there are no guarantees that the virus will not be transmitted in any specific instance. Other factors may also influence the likelihood of transmission, such as the presence of certain sexually transmitted diseases in the negative partner and also whether a man is circumcised (which has been shown to be a protective factor of negative men engaging in vaginal intercourse with a positive partner). A newly emerging HIV prevention practice is the use of pre-exposure prophylaxis (or PrEP) by HIV-negative people who are having unprotected sex with partners who are of positive or unknown status. This involves the negative person taking anti-retroviral medications, the same ones used by HIV-positive people, in order to prevent a new infection. The issues involved are complex, but PrEP may be ideal for members of couples of mixed HIV status, and this is an option you should consider discussing with your physician. It is possible for someone with a drug-resistant virus to transmit that specific virus to another person. That means the newly infected person would be starting off with a drug-resistant virus. It would be standard practice to have a resistance test performed prior to starting antiretroviral therapy. A drug regimen would be selected depending on the outcome of that test; the person would start with ARVs for which there is no resistance.