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Love a bit of trial data so even though we only have one measure from Pfizer trial, thought it might be useful to go over what it might mean in vaccine trial context 1/n
First thing is that the effect size is exceptional. Lower bounds of confidence probably around 75% means that when they get to their prespecified number of cases it is unlikely to change much from a regulatory perspective (on efficacy at least). 2/n
Vaccine safety- Important but context is vaccines are exceptionally safe in general. Novel technology but at present no causes for concern. 3/n
Next is the specifics of the trial which enrolled very quicky due to current terrible state of COVID generally (small positive from failure to control in certain places). This means the data on safety will be modest compared to ChadOX which has several months on them. 4/n
Trial population- is going to be critical. Age is going to be the most important variable but then subpopulations are important in roll out (example is pregnant women who are excluded by trial criteria). This would in an ideal world influence the strategy for implementation. 5/n
...but probably will not, as political considerations are going to be influential. For example the likely prioritisation of elderly/care homes and hospital workers will be a strategic decision not based specifically on trial data. 6/n
Endpoints- I am surprised not getting more attention. "case definition" of COVID varies quite a lot between studies. In Pfizer they even have 2 separate definitions in one study and we don't know which they refer to in press release. They have taken a low bar approach. 7/n
Endpoints 2- for example a sore throat only gets counted. in definition 2 it goes down as low as fatigue or runny nose! In some ways this is a good thing as getting closer to likely relationship to transmission and not just preventing severe disease. 8/n
Endpoints 3- ...but means not clear if preventing severe disease yet. This will take longer to become apparent but logic suggests it will follow in time. 9/n
Impact on other vaccines- This is really important and to my mind our biggest challenge. Given how quickly existing studies are likely to report, how do we keep enrolling in studies. We need to do this because we want a strong set of vaccine options but also to be able to... 10/n
.... flesh out the huge remaining questions. All sorts of ethical questions and trial process questions raised here. Not simple answers. Needs clearly communicated to public to get them to understand this is the beginning of the end not the end itself. 11/n
Last thing is to address scientists already complaining about lack of transparency. PLEASE STOP. You undermine confidence. Pfizer have immediately released headline results within days (I understand) of Data Safety meeting. They have to do this by market rules but the data.. 12/n
We should all be positive. Not the end but I believe it is the beginning of the end (sorry Churchill for misquote!). Heap of work to do but I think the roadmap is clear. Science is amazing. #MedTwitter need to redouble and counteract the spread of bad information.
Missing 13/n. First time I have done a long thread! .. the data will take weeks to QC and hard lock. No great conspiracy just normal trial process. Have patience and maintain trust.
