Some critics say that ending polio has become Bill Gates' "white whale."
Why not just settle for the huge drop in polio cases that we've seen over the past decade and then spend money on other things that kill so many more kids, like diarrhea and malnutrition?
"Polio is special," Gates tells NPR's Robert Siegel on All Things Considered. "Once you get it done, you save $2 billion a year that will be applied to those other activities. There's no better deal economically to getting to zero."
Some other news. For the second time in less than a week, Afghan and Pakistani forces have exchanged fire along their shared border. The countries clashed again yesterday over a gate that Pakistani forces have been building on what Afghans say is their side of the line. The roots of this problem run much deeper.