Yes, Vitamin A deficiency is a problem, and Golden Rice can treat it. You know what else can? Pretty much any other food with Vitamin A. Why do we need to create an entirely new kind of fortified rice? Why not just, say, give these people carrots?
These people are vitamin deficient in their diets because they are poor. Making golden rice is solving the wrong problem. What we need to do is end poverty.
Should we work towards ending world wide poverty? Yes.
In the meantime, just like Canada added iodine to salt to prevent a whole host of diseases at the turn of the 20th century, so to can we add things like vitamins to very basic foodstuffs for the third world.
> Why not just give these people carrots?
Because that is extremely costly, difficult, and destroys local agriculture and has a host of other negative externalities. Furthermore many people are too proud to take a handout, but selling their farmers better grains is achievable.
It isn't costly at all. We can feed everyone on earth for a few paltry billion; food is not expensive. We choose not to. Golden rice has its own technical hurdles and is only solving a single nutritional problem.
These people are vitamin deficient in their diets because they are poor. Making golden rice is solving the wrong problem. What we need to do is end poverty.