Living near Danville, VA when I was 12, had on a brand spanking new unwashed yet, pair of heavy jeans. Got hit by a copperhead on the knee before I even saw it. Those jeans saved me, only a small little more than a scratch with one fang. the whole knee area of the jeans was soaked kinda yellow, and turned hard crusty. My folks took me to the hospital, got a shot and sat in the waiting room for a couple hours - no problems, and sent home.
I was incredibly lucky, and I do watch for snakes with every single step, always have ever since.
In the local paper here there was a lady mowing her lawn hit by a copperhead - she spent over a week in the hospital.