The chronic fatigue virus: de-discovered?

One of the most important things that virus-hunters do is "de-discover" links between viruses and diseases. In other words, they follow up on studies that indicate a link and see if it can really hold up. Last year, a team of scientists published a paper in Science in which they reported that 67% of people they studied who suffer from chronic fatigue syndrome carried a virus in their system known as XMRV. Only 3.7% of healthy people did. That association then morphed into the idea that XMRV actually causes chronic fatigue (a condition that afflicts an estimated 60 million people worldwide). Some people with chronic fatigue have sought anti-viral medicines based on the finding, declaring that they've felt better as a result. But when a lot of other scientists tried to find XMRV, they failed to do so.

Today Science itself is publishing two papers that cast even more doubt on the link. In one study, scientists looked at 61 samples from the same medical practice where the original samples had come from. They couldn't find any XMRV in people with chronic fatigue.

Another study supports what a lot of experts have been saying recently: that XMRV was not ...