Earlier quoted context omitted.
Thank you for volunteering and putting your health on the line for the benefit of us all. Even if the risk is small, it takes courage. I'm assuming you also don't know if you got the active substance or a placebo?
> I'm assuming you also don't know if you got the active substance or a placebo? Yep. In the UK, they used an existing, unrelated vaccine with similar side effects as the control so it wasn't obvious which one you got. In some countries and for some of the other vaccine trials, they are just using saline as the control so it seems like a lot of those people would know.
You can tell the difference in getting a vaccine shot and a shot of saline?