Patterns of drug resistance in blood and in semen were similar, but not usually the same. In fact, the resistance patterns matched only once. The majority of HIV in the genital tract is genetically different from the types of HIV found in the blood. This suggests that HIV evolves differently in each 'compartment', thus complicating treatment and efforts to prevent transmission of resistant virus. These data show that transmission and treatment of drug resistant HIV is likely to become a significant public health challenge for the HIV community.
Larger studies are underway at a number of centers.