During the last bird flu scare quite a few people invested goodly sums of money, often a thousand dollars or more, to lay in a supply of Tamiflu. Of that a good part has expired and now we find out that it may be of little or no use with the next round of viruses.
Bottom line is that nobody knows what is coming and, as always, funds are limited so it is important not to get too far ahead of ourselves and invest too much based on what we assume, fear, will happen. Get too far ahead of yourself you may find yourself with the wrong supplies and no resources left to get hold of the right stuff.
IMO the best plan is to focus on supplies that can be used in a variety of ways and situation. To avoid, for the most part, stocking things that have but one use.