I think we all understand the idea of how to trace HIV transmission – by sequencing the viral genomes of different strains and looking at differences, we can map the phylogeny of the different strains. In doing so, we can see who infected who. Here’s an article that summarizes this pretty well.

I thought this was pretty cool because when HIV-positive individuals are told about using condoms and how that prevents infection of HIV-negative individuals – but less often do you hear about preventing transmitting another strain to an already HIV-positive individual. The consequence of infecting an already infected individual is introducing, to some extent, a new virus. Depending on viral loads, re-infection might actually change the viral population dynamics and introduce new mutations and phenotypes to the viral landscape in the individual. The primary consequence of this is that re-infection may lead to drug resistance and dramatically affect treatment course.

I didn’t know to what extent this idea of super-infection was known among the population, but this study shows that the possibility is actually very well known. While this all seems pretty logical and understandable,  I can’t help but think about what this means in the realm of public health – How does this affect how health professionals counsel people living with HIV/AIDS (PLWHA)? Should we treat couples together, regardless of HIV status? Should we sequence strains to see where individuals were infected and use that to develop specific prevention strategies?