So why are the schools of thought different on the two sides of the Atlantic?
Up to a point, I think it reflects the fact that our illness is heterogeneous and that antivirals may help a subgroup - just as rituximab may help a subgroup.
Why does anything ever become fashionable? Either because there are no alternatives or because of heavy promotion by influential people or because there is actual, real substance to a particular idea. Then there's the other factor, which is like genetic drift; randomness.
I can't really speak for the US situation in much detail but it certainly does seem easier for US doctors to try a treatment, previously approved for another illness, on pwME. How much this is down to private health insurance and how much to an inherently different approach, I cannot say. But if one doctor tries an antiviral, for example, and sees improvement, then other doctors may be encouraged to do the same. The problem might be if this is being done without outcomes being properly assessed. How effective is the treatment, really? The freedom to use a treatment, while providing benefit to some patients, may discourage full scale trials. So it will never be used by doctors who insist on evidence. Also, ultimately you want to know
why something works, not just that it does.
It's fascinating that of all the countries where the fortuitous rituximab discovery could have been made, it was Norway with a population of only 5 million.
How many pwME in the US (or the UK or anywhere else?) were treated with rituximab for lymphoma. How many of them noticed an improvement or complete remission in their ME? How many of them commented on this to their cancer doctor or to their ME doctor? What did the doctors make of it? What factors were involved in all these individual observations going no further. You'd have thought that of all countries where a health care system would have allowed for more freedom to use a drug off label, it would have been the US that stood the greatest chance of someone getting curious enough. Did perceived wisdom make the ME doctors say something along the lines of "Well the only thing in the human body that rituximab acts on is CD20. We know that there is a heavy infection load in our patients so using a therapy that depletes B cells seems a bit risky"? Were the cancer doctors secretly thinking "Yeah, yeah. We know that CFS is psychological. You've just had a brush with a serious, potentially fatal illness and have now bucked your ideas up"?
Bizarrely, it was Norway with a tiny population but a very high per capita income and a great health care system. Unless you have ME in which case I'm sure it sucked every bit as much as the UK does.