With big data, when you actively look for patterns you always find them; this is how hedge funds have been operating for years. The purpose of the technology is not to make predictions, but rather to confirm existing trends and possibly identify new ones.
Proper way to utilize big data in this case would be:
1) to assist the CDC in confirming or refuting trends observed in the field
2) to offer additional correlations (such as: are people living closer to highways more sensitive fo specific strains of flu)
3) to provide long-term indicators facilitating the assessment of medication and other flu containment factors
Big data is not a magic eight ball but it's not a piece of shit either.