You know, I thought it was very interesting when Dr. Cohen presented the Tysabri option to Herb. Like you, Gretchen, Herb had been on his medication for 6 years, and it was working fine...until this excacerbation (which, considering what COULD have happened, it was fairly mild).
I get the feeling that the thought process in the neurology field is "if you can, get them on Tysabri as soon as there is an exacerbation...don't waste time." But, the doc did tell us that had there been no flare-up, Herb would have remained on Betaseron. Most likely, this is due to the fact that Tysabri is considered a "second line therapy" and it's so strictly controlled though the TOUCH program, due to the PML.
And, earlier I spoke to the nurse in charge of the infusion and asked her about other patient's reaction to the medication. I guess the overwhelming side-effect is FATIGUE (as if someone with MS needs more of that) but, it appears to her that, as the patient gets more infusions under their belt, the fatigue fades. Herb's biggest concern is squeezing in the therapy around his work schedule and how badly will it interfere with that. Fortunately, his co-workers are incredibly supportive which is a huge, huge help.
Our thoughts and prayers to all!