Phase I/II study of COVID-19 RNA vaccine BNT162b1 in adults

I was using the terms interchangeably since they publish the trial results as a study in medical journals but ok. Specifically, which phase of the Pfizer trials? They got the EUA after completing three phases.. Phase 1/2: https://www.nature.com/articles/s41586-020-2639-4.pdf Page 10 shows 0 deaths in the trial with the most severe adverse event being a "disturbed sleep" event. Phase 3: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2034577?articleTo... This was the big RCT trial with 43,400 participants. 2 participants in the medication group died, 4 participants in the control group died, so the vaccine cuts deaths from unrelated causes by 50%! (joking of course) In any case, they didn't even include all cause mortality as an end point. So again - please provide a link to whatever it is you're referring to because "trust me bro, more people died" doesn't really cut it.

What’s interesting is that in the initial trials, moderna tested 50, 100 and 250mcg in humans and ultimately decided on 100mcg as the sweet spot. https://www.nih.gov/news-events/news-releases/nih-clinical-t... Meanwhile pfizer tested 10, 30 and 100 and ultimately settled on 30mcg as their sweet spot. https://www.nature.com/articles/s41586-020-2639-4 Was this due to differences in the vaccine itself, different study environments, or different tolerances for the balance between side effects and effectiveness?

It's important to note that the AstraZeneca vaccine is adenovirus based [0], not mRNA based like the Pfizer and Moderna candidates. It was to be expected that this approach could cause more complications. mRNA vaccines have their own issues, but they do not involve live viruses being injected [1]. Instead they use lipid nanoparticles as a substrate to enter the body's cells [2]. [0] https://www.astrazeneca.com/media-centre/press-releases/2020... [1] https://www.phgfoundation.org/briefing/rna-vaccines [2] https://www.nature.com/articles/s41586-020-2639-4