Preamble: Dr Cheney has observed that immunomodulators such as imunovir, that shift the immune system balance from a Th2 (antibacterial) response to a Th1 (antiviral) response, often get good results in CFS patients initially, but then the gains seem to disappear after some months. Many CFS patients have experienced this themselves. Dr Cheney speculates that the reason for this is that the body gets used to immunomodulators: that the body builds up a tolerance to them after some months, thereby explaining why their good effects wear off. Dr Cheney suggests you should take regular breaks from immunomodulators, to prevent this tolerance from manifesting. New Hypothesis: It occurred to me that there may be a different explanation for why the good effects of Th2 to Th1 immunomodulators disappear after a few months of usage, which is as follows: When taking Th2 to Th1 immunomodulators, and the immune system shifts towards the Th1 response, this works well for killing off your viruses; but since at the same time your Th2 is down-regulated, so it is conceivable that the bacteria in your body then start to proliferate more and more, because of the diminished Th2 response. Thus although you initially feel better due to a reduced viral load, you may soon start to feel bad again, because the bacteria are building up in your body. From the viewpoint of this alternative explanation, the reason pulsing your Th2 to Th1 immunomodulators (having breaks from taking them) is helpful may be less to do with preventing a tolerance from manifesting, and more about allowing the Th2 immune response to ramp up again for a while, in order to kill off the bacteria that proliferated while you were on the Th1 side. However, presumably during these regular breaks from taking immunomodulators, the viruses in your body will unfortunately start multiplying again, while the bacteria are now being killed by the Th2 immune system. Indeed, perhaps CFS arises in the first place due to patients having both pathogenic viruses AND bacteria in their bodies, and so that every time the immune system fights of one type of pathogen, the other type then sneakily re-emerge. In a sense, people with CFS may be trapped in a long dark alley, with viruses attacking from one end, and bacteria from the other. When you direct your energy to fight off the viruses, the bacteria come to get your from behind, and vice versa. So you never get out of the alley. I don't know enough about the function of the immune system to say with any certainty whether the above scenario is in fact possible, but I thought I'd throw it out for general discussion and comments. Possible Way out of the Alley One possible solution, it would seem, to this dark alley scenario is to take antibiotics at the same time as taking Th2 to Th1 immunomodulators. In this way, you let the Th1 immune system tackle the viruses, and let the antibiotics keep the bacterial populations in your body in check. With this approach, you would not need to take any breaks from the immunomodulators; so you maintain an uninterrupted ongoing full-on Th1 assault on the viruses, until they are hopefully pummeled into submission. Note that if, on trying this Th2 to Th1 immunomodulators + antibiotics approach, it does seem to work (meaning that gains experienced do not disappear even after several months on continuous immunomodulators), it would indicate that there is something to this idea. Ideally, if possible it is best to take the right antibiotics (or antibacterial herbal supplements): ones that best target the specific pathogenic bacteria you have in your body (if you have this information at hand, from an intestinal stool analysis for example).