I take a break from it for the same reason cheney and other cfs docs say to take a break from immune modulators ie your body becomes less responsive to it. immune modulators are different to arv's and av's as they stop the viruses from replicating and stopping and starting these drugs allows the viruses to build a resistance to the drugs, where as the immune modulators used continiously loss their ability to stimulate interferon etc if that makes sense, they work in different ways. reading up on cycloferon today, they seem to do courses of treatment with cyclo and the benefits last upto a month after finishing in some illnesses, maybe by dropping the viral load down in combo with arv's/av's. I keep taking famvir/av's but probably should have restarted the cyclo earlier as i left it for 6-7 weeks, but also wanted to get some testing done while off the cyclo. testing on the cyclo was very positive as well as my symptoms. my lymphocyte(always high) subsets were down lower then i have ever had them measured before even while on famvir alone. I did still have some lingering fatigue which i think was due to my poor adrenal hormone(dhea/cortisol) testing, which im trying to improve but overreacting to treating this problem, so still juggling this around. Since of the cyclo though, i feel like i have had another viral type crash which was when i last got tested, so straight after the testing i started back on cyclo again. Let us know how u go on the cyclo wrthster, delivery time for cyclo seems to take awhile but thats to australia, way down under, lol.