I'm looking for weekly data on all new cases at the clinic, city, or county level, for all previous flu seasons. Does anyone know where I can find such a dataset?
I'm not aware of any definitive source, but this is doable piece-meal I think.
New York Data starting from 2009-2010.
Google has a lot from FluTrends.
Trends in Recorded Influenza Mortality: United States, 1900–2004; I'm assuming datasets are cited/linked to here.