@khnews tackled this issue. @US_FDA will require covid-19 vaccines to be at least 50% effective. But how do you define "effective?"

Effective at preventing infection? Or any symptoms? Or hospitalizations or deaths?

https://khn.org/news/scientists-warn-americans-are-expecting-too-much-from-a-vaccine/ https://twitter.com/LizSzabo/status/1322243586113572865

CDC's Tom Shimabukuro said they also hope to launch an email-based system to monitor vaccine safety. https://www.ustream.tv/channel/VWBXKBR8af4

From @cdcgov: Nearly 9 million cases

Live from the @CDCgov