FYI, nice TechRepublic article on how Walgreens is monitoring flu in the US. The data is based on the number of anti-viral prescriptions filled at more than 8,000 Walgreens across the US, and it comes out days ahead of the weekly report the US Centers for Disease Control and Prevention (CDC) releases every Friday.
Flu prevention: Walgreens tracks influenza activity with Esri location analytics - TechRepublic
Nice interactive map,
https://walgreens.maps.arcgis.com/apps/MapSeries/index.html?appid=40d0763cd3cc42428b26f85202108469
Enjoy,