Name Info Provider Link
Flu free resource MedlinePlus Health Information https://medlineplus.gov/flu.html
subscription/membership/fee required Ovid Technologies, Inc. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=linkout&SEARCH=31822885.ui
subscription/membership/fee required Silverchair Information Systems https://academic.oup.com/jid/article-lookup/doi/10.1093/infdis/jiz656