It's Possible to be Too Prepared: All those bird-flu vaccines that the U.s. is stockpiling are expiring earlier than expected:

The initial doses of bird flu vaccines that were stockpiled by US authorities are less effective now - they lose their strength over time. As the vaccines have a shorter 'shelf-life' than was first expected, it is possible that the US stockpile would now cover one million fewer people than previously thought.

But don't worry. The government is spending millions more to replenish them. Just in case.