I'm glad to read this article. Here is my opinion, which I have stated before: I've found the controversy around the different variations, XMRV and MLVs, to be overplayed from the beginning. Dr. Lo "started it"; yet in the Q & A period afterwards, he contradicted that impression of different viruses when he quietly said that these variations, this degree of variability, was both normal and expected among viruses. He gave the example of hepatitis, as I remember. What he barely mentioned under his breath was the possibility that differences in patient cohorts could be causing the differing results--with the CDC's paper.
My feeling about all this, starting with Dr. Lo but going on to the other commentators, both in the media and here, was that the viral variations as an issue was overweighted. It was a red herring, a false trail that most charged right down, while the cohort difference in particular was greatly underweighted. To me, there was politics in this. I think that the CDC has to save face/have its face saved. What is useful to this end is to criticize the opponent's work, while the CDC gets time to step by step move away from its old position. It must not be bluntly confronted or shown to be wrong. Why? The CDC is the biggest player around, by far, with the greatest resources. Scientists needing contracts and research dollars respect that. The small players like the WPI are not only safer to criticize and challenge, but this is how it is going to be played, until the CDC can move slowly from its old position, keeping its respectability intact. Its respectability is important as the guardian of public health.
That is how I regarded the presentation by Dr. Lo and Alter's findings and the commentary afterwards. There is a political context to this science. We want the science to move forward, but are wise to consider the politics.
The best thing to do? Allow the CDC a graceful way to change position, is one suggestion.