Hi Daisy and welcome to our Tysabri forum!
Your first question is hard to answer because everyone has a different insurance plan. The Tysabri program used to investigate your insurance plan and let you know approximately what you would have to pay, if anything. I am not sure what they do now, but someone who has started recently should be able to answer that better than I can.

In addition, everyone goes to a different kind of infusion center. Some are private, some are hospital based and some are physicians office based. If it is hospital based your insurance should cover it under hospital benefits and you have to read your plan and find out what they cover(ie: 80%, 100% etc.) Whatever they don't cover is your responsibility. If it is physicians office based it's whatever your plan covers for office visits, and if it a private infusion center, it's based on whatever your insurance plan will pay for that.

Biogen cannot help you with infusion costs, only with the cost of the drug, but your infusion center may have a program that helps with cost of infusion. If it is hospital based, you may qualify for a reduced rate based on your income.

Vit. D and B 12-
I had low Vit. D levels too,I took 5000 units D3 a day for a year and then reduced it to 4000. My levels are high normal now, and they stay there. I don't have low B12, but there are a lot of folks out on the regular forum that can help figure that out with you. Neither of those matter when it comes to infusion, just general health.

I have low iron levels and take an iron pill every day. I will find out if it helped at my next appt. and if not the doc will be increasing it or changing it to slo-fe for better absorption. I am also increasing red meats, dark green leafy veggies and other iron rich foods and cooking in cast iron pans a lot more than I was doing, all in hopes that I can increase the iron levels without the added expense of a prescription supplement. The increase in iron should help increase red blood cells too.

Tysabri infusions take 2-3 hours. You go in, they ask you a few questions, you get a brochure, they hook you up and you get the infusion for an hour. Every infusion center is different but they all are supposed to follow the protocol of an hour for infusion, an hour of observation to watch for adverse side effects, asking the questions prior to infusion and giving you the brochure.

Some people have some side effects. Some do benadryl before infusion, some people are tired after infusion. Some have no problems at all.

Best thing to do is make sure you are hydrated before your infusion, drink LOTS of water so they can find a vein easily, eat before you go, bring something to keep busy with and RELAX.

My infusion takes 3 hours total and I use it for my monthly break! I'm always at 100 miles an hour in my life and the infusion makes me slow down and just sit. I read, watch TV, have a snack, a hot drink, and just chill. It's almost my only "me" time during the month and I take advantage of it! I used to be raring to get out after infusion but my infusion center refuses to let me go before my time is up so I have learned to deal with it... (after 47 infusions!)

Hope all goes well with you! Let us know how it goes!