JCV has nothing to do with Ocrevus. It is a problem related to Gilenya, so unless "YOU" plan on taking Gilenya it should not concern "YOU"
When it comes to side effects read the forms they give "YOU" if "YOU" can as they are in small print. Legally they have to note all side effects encountered in the trial on the Patient Information pages that never get read. At least I never have. Get to know your chemist\pharmacist really well and talk to them. I have found after the second ER visit I actually asked a question and only OD'd once more. I can assure "YOU" that opioids are not really very useful. At least not for Trigeminal Neuralgia.
So, my friend, the point is. Without being too crass, open your mouth and ask a question of a professional before "YOU" get scared, ask and learn your risks. Ask until "YOU" are comfortable, but do not procrastinate too long. ms loves when "YOU" delay. I took six months but then was very hard on myself for several years. Do not just believe the first thing that "YOU" see or some rumour. LEARN LEARN LEARN all that "YOU" can about this condition.
I will tell "YOU" that it is a very very long-term condition. I am twenty years along and I expect that I should do another twenty or thirty years barring stupid accidents, of which I am known for. Do not despair, just take a moment. If "YOU" would like to, talk to your dog and have a cry. Having a cry is really okay. I get a little weepy sometimes, not sure why but that is a consequence of our condition. "YOU" are not weak or any less than anybody else, "YOU" just have this "something" causing mischief in your body. That nobody knows why or where it comes from. It really is fun to look at all the crazy ideas people have. Most absolute rubbish though, but still funny.
ms, today tomorrow and the next day is a DOABLE disease. All "YOU" have to do is make a choice, and do ms.
Make that decision, LEARN and do not be scared