I agree that we have to keep options open in terms of models that include viruses and those that do not. I am a bit worried, though, about a blanket fear of 'immunosuppression'. My point about immunosuppression was that if a virus was present at least some sorts of immunosuppressive therapy should make the presence of the virus more obvious. That would not necessarily have any implications for whether or not the person felt better or worse. I am doubtful that worsening following the use of drugs that might have an immunosuppressive effect is itself reliable evidence for infection. What is puzzling about the steroid situation is that the doses you mention are not really immunosuppressive. If anything I would tend to regard them as the sorts of levels normally found in an active immune response. When the body is stressed by infection steroid levels go up by this sort of amount and if they do not the infection may be much more dangerous. At low doses steroids are in effect 'immunopermissive' or 'immunonecessary'. One of their problems, though is that shifting levels artificially by medication can upset the progress of a lot of diseases so for many of the conditions like RA, for which they were originally developed, we now think they may be more trouble than they are worth. These debates are useful, but I think one has to be careful about the detail and not lump a lot of things together under an umbrella term like immunosuppression. I am aware that a story of immunodeficiency relating to NK cells has been popular, but so far I cannot make a simple analysis along those lines add up.