I haven't had any herpes flairs, yet ( I have corneal herpes), but I have had many itchy inflamed skin lesions on my arms, breasts, back, thighs, and scalp. After 12 infusions, my neuro says I have to take a "Tysabri Vacation" to lessen the chance for contracting PML. I'm fine with this, but it will be interesting to see what happens in the next 3 months.