This blog, recently on various vaccines, seems a good one to me. by @dereklowe on the AAAS site. Better than one of our experts here saying ridiculous things such as ""That’s for us to know and you to find out". https://blogs.sciencemag.org/pipeline/ 

On why they switched their position and on "That’s for us to know and you to find out" my own view, and yes as an expert in communication, is that they felt they might undermine confidence (it's what they say anyway). 1 in what's gonna happen anyway and 2 cause anti-vaxxers.

Poor expert communications. Because all kinds of sad assumptions about communication, politics and human psychology are contaminating what they say. Much better to give the actual expert part of expertise and if there are assumptions state these clearly, as per e.g. @brianrstill

On AZ, seems to me that 1 there are good reasons for using it ..*maybe 100% no hospitalisation 2 choosing/funding it fuzzy in Australia .. does not bode well for logistics but we live in hope 3 there's not evidence as yet for herd immunity. Generally the data for it all a mess.

Generally this is a good thread on dealing with science and expertise https://twitter.com/ewanbirney/status/1345728321624150018?s=20