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Ganymede25 t1_isdwn2m wrote

Maybe it was because we were all paying a lot of attention to any details associated with the vaccine. For instance, both the experimental and control people would have pain at the injection site, but only people receiving the vaccine would have the injection pain go away and a new pain show up 6-12 hours later that would last for a day. That is the result of an immune reaction. Saline would not do this. When you combine the delayed pain with a slightly elevated body temperature and a slight headache, it is pretty easy to tell when you are sort of focused on whether you got the vaccine or not.

Regarding the 100% wrong for the placebo, maybe you got confused on my comment. In the trial, 50% of the people received the vaccine and 50% of the people received saline. The people who received the saline knew that they had no symptoms and were 100% correct that they didn't get the vaccine.

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slouchingtoepiphany t1_ise8sfe wrote

I did misunderstand your previous comment. It's conceivable that people who guess correctly had experienced delay hypersensitivity reactions at the injection site (with vaccine, but not with placebo), but it's also possible that the group of correct guessers was small, say 3-6, and with a smaller number it's easier to obtain a series of correct guesses by chance alone. It's like flipping a coin and having it come up heads 3-4 (or more) times in a row. Statistics can do that. However, I think it's more likely to be the delayed hypersensitivity reactions.

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