JC virus percentage etc

Hi after a year ish on copaxone, I had optic neuritis and that meant I had to change my meds onto something stronger. I have now been having tysabri infusions for nearly a year. However I was tested for the JC virus, before i started the infusions and I do have it, but only 1.2% so the risks of PML were the same as if i didn’t have it, yet they decided that I should have the infusions every 6 weeks instead of 4. I recently had a MRI head scan and after receiving a copy of a letter sent to my gp, I do have a couple of new lesions, although the neurologist seems to think they occurred before my infusions began and there’s no concerning or atypical findings to suggest PML. I do have a video consultation with him next week.
What I am wondering is, will I need to ask for another JCV blood test? can the percentage of JC virus I have change or rise? Last time I spoke to the nurse etc, I got the impression my meds will be assessed again and I’d need to change again. But with the brain scan not showing PML, will that mean I can stay on the tysabri infusions? any thoughts? please thanks