On Tysabri for 2 years, positive JC virus test .....

… just that really. Anyone else in same position as me? Any thoughts?


The test was not available at my hospital when I started Tysabri - it now is and I was offered it. However I have so far said no thanks. In a moment of doubt I asked the infusion nurse how many people are taking it and what results they are getting. Apparently all but three of us have accepted the offer of the test - however 80% of those tested have come back as positive. For me this means the chances are I am positive. Knowing I am positive would not make any difference to being on the drug (this in itself would not make me stop it) - and would not remove the need for vigilance. For you it means you are not unusual = most people as I understand it would be positive in any case.


I am also positive for JC virus. I had been on Tysabri for 2 years when I came off it last April. Then I went to Bruges for CCSVI treatment, which wasn’t successful (they couldn’t sort out my veins). So I had been off Tysabri for about 8 months when I had a bad relapse in December. Neuro said it was just the MS doing its thing with nothing to " damp it down." Now the MS nurse says I should go back on Tysabri. I was hoping they would offer Gilenya or something else. I still manage to walk with a stick, but cant get about as much as I used to, have to get taxis to places I used to go to on the bus. By the way, they told me my risk of getting PML was 1 in 500 when I was on Tysabri. I was stable and doing well for 2 years on the drug. It IS tempting to give it another shot, but I worry about “sod’s law” having made such efforts to get away from the horrible drug.

I have only met one person who has mentioned the result of the JC virus test to me and it was positive. This person has decided to continue with monthly infusions anyway.

I think it’s a personal thing with Tysabri what you choose to do. Listen to the advice of your neuro and MS nurse to see what they think is best for you. And also the folk on here. At the end of the day though it’s your body and your decision. For me although Tysabri has stopped my relapses the condition improvements have now levelled off although I am better than I was before I started treatment.

What is the JC virus?? sorry for my ignorance but not heard of it? Is it to do with the infusions? must be

Its the John Cunningham Virus if you carry it you could develop PML (Progressive multifocal leukoencephalopathy) if you don’t then the PML risk is negligble

Hi, thanks for answering this question. I was about to ask myself.

So does going on Tysabri increase one`s chances of getting JCV? I know little about this subject.

Very worrying, isn`t it?

luv POllx

If you are on Tysabri and carry the JC Virus your risk of developing PML is greater than if you don’t. I don’t think Tysabri increases the risk of carrying the JC Virus. But I’ve never thought to ask that.


I am 6 years on Tysabri and positive for JC virus. My consulatnt said he lloks like the longer you are on the drug the less chance of developing PML. This is not concrete but he says a strong correlation.

I am not worried!


Hello again,

Just to mention that it seems to be well established that the period of maximum risk of PML is between 2 and 3 years on Tysabri. After that the risk goes down a fair bit, but doesn’t disappear. I’m still undecided about going back on it. As has been said, its a personal decision.

Hi Jackie,

I’m going on Thursday for my 44th infusion I’m sorry I can’t help with your worries about being positive for the JC virus the test wasn’t avaible when I began Tysabri they haven’t said anything about having the test but I did tell them the’d be aswell spend the money on something else as doing the test on me I have a fairly good life now again thanks to Tysabri and wouldn’t be coming of it.

I understand people that are about to start Tysabri and don’t know what a differance it can make to your life or It maybe hasn’t worked so well but its worked great for me and there’s no way I’d risk stopping and risk going back to the way I was before.

Thats just how I feel.

Mark x

I didn’t realise there was data on the risk of PML after 2 years… I thought studies had only gone up to this point? I’m just wondering where you saw this as I wouldn’t mind having a read!

Thanks x

I didn’t realise there was data on the risk of PML after 2 years… I thought studies had only gone up to this point? I’m just wondering where you saw this as I wouldn’t mind having a read!

Thanks x

This is from the Barts & London site.


I’ve been on Tysabri for 5 years and tested positive for the JC virus. I honestly don’t give it a second thought.

I would really appreciate it if panelofone could update us on what happens to them. I had the idea that you run a high risk of ‘rebound relapses’ if you go off Tysabri but this thread suggests this doesn’t happen to everyone. I know a couple of people who have Tysabri where I do who came in for steroids for relapses pretty soon after stopping Tysabri.

There is plenty of information concerning possible rebound activity on the Barts & London site.
This lot should get you started.