Tecfidera & JC virus

Hi everyone

I haven’t been on hear for a wee while but something has cropped up that I need am a bit worried about.i recently had a routine blood test a couple of weeks ago unknowingly they tested for the JC virus unfortunately the test has come back positive my concern is that I have been on Tecfidera for just over a year now without any side effects and it’s been great not having to inject I am now of course worried that I am now JC positive my other bloods are fine lymphocytes level is OK.i just wondered if there is anyone out there with the same problem.

My ms nurse said I would not be taken of Tecfidera as long as my lymphocytes level didn’t change also I will be getting more MRI scans but I can’t help from being a bit scared.


JCV only really runs the risk of turning into PML (the true cause for concern) if you lymphocytes drop too low and / or do not recover.

This is true for any human, not just those on a DMD. You should be reassured by your blood counts being okay.

However, in order to provide the absolute best care for your health and well being, MRIs have been ordered for you. And this is completely standard; during my last MRI, i took a peak at my requisition forms and they stated that i was ‘at risk of PML’. I do not know if i am JCV+ but the fact that DMDs are taken daily, it is simply the nature of the beast.

If you are having regular blood counts (and i have mine every three months, even tho my neuro was happy for twice annual) you have nothing to be scared about.

so go and get on with your life!

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Hi Annie57

I am waiting for my JCV test results any day now. I have also been on Tecfidera for over a year with no side effects but my lymphocytes are too low now and getting lower. I suspect they might stop it even if the JCV test is negative. It’s disappointing but there are alternative DMDs.

My understanding is that the majority of people (70-90%) are JCV positive and as long as your lymphocytes are OK then you should be OK too. I think it works out well for most people.

It sounds like you are being properly monitored. If it were me I would get on to the MS nurse or neuro with my questions to try to ease my mind as much as possible.

Good luck with it all.