HIV sequences cannot prove guilt
19 September 2007People infected with HIV might well want to know who gave it to them - but the genetic sequence of their virus won't tell them.
The virus is now routinely sequenced in each infected person to uncover drug-resistance genes, but virus sequences have also been used in several high-profile court cases by lawyers seeking to show who infected whom. This has led some HIV carriers to wonder if they might be able to do the same.
"The data won't work for that," warns Deenan Pillay of University College London - because HIV evolves too fast. This means that even though the viruses from two people may look similar, other local viruses may even be more alike. Analysing them can't show whether A infected B or vice versa, whether it went through a third person or whether both were infected by another person (BMJ, DOI: 10.1136/bmj.39315.398843.BE).
However, the British database - now the world's largest collection of viral sequences from a national epidemic - could answer other important questions. For example, it could tell us whether certain strains tend to spread among certain risk groups, or where the super-spreaders of HIV are.
From issue 2621 of New Scientist magazine, 19 September 2007, page 5