It's interesting that this article states the H274Y mutation...

It's interesting that this article states the H274Y mutation will cause resistance to the IV drug peramivir (recently approved by the FDA for emergency use) as well as oseltamivir. Zanamivir, on the other hand, still works in the face of this mutation, due to its chemical structure and mechanism of action, and not simply because it is less widely used:

http://content.nejm.org/cgi/content/full/353/25/2633

(Thanks to a poster from a few weeks ago who alerted me to this paper).