Submitted by Nearby-Cloud-3476 t3_y3xbur in askscience
dogquote t1_iscjqxo wrote
Reply to comment by Ah_Go_On in Does a reverse placebo exist? by Nearby-Cloud-3476
This is crazy amazing, and I learned something today. I wonder how much of this is related to vaccine apprehension. Is nocebo studied in trials along with placebo?
Ah_Go_On t1_iscmfz5 wrote
In trials not really since all participants in trials must sign an informed consent form and in that process are informed of the details of the trial's objectives and possible outcomes, including the fact that they may receive a placebo, assuming a placebo is used in the trial. Nocebo is more often investigated retrospectively for ethical reasons.
I don't doubt that some people who didn't want (e.g.) a COVID-19 vaccine but who had to get it to keep their job (or for whatever reason) may well have experienced more side-effects than others. But this is where it gets complicated, cos some people who didn't want the vaccine, say, because they heard other people became ill after getting it - then they get it and are psychologically determined to not feel ill, cos they're "not a pussy" or whatever. But such people may still get destroyed (temporarily) by post-vaccine flu-like symptoms because ultimately individual genetic/metabolic variation is a stronger determinant of treatment response than psychological disposition (but it's not always as simple as that!)
Edit: this is a very interesting paper on side-effects in vaccine placebo arms:
grandmabc t1_iscqsq3 wrote
Before I had my first covid jab, I was convinced it would give me flu like symptoms. I fully expected to be under the weather for several days... but nothing, no side effects at all. Now I'm wondering why I didn't get a nocebo effect.
Ah_Go_On t1_iscvoqj wrote
Because psychological phenomena are at least as inconsistent as they are powerful :) Every imaginable factor/circumstance affects patient responses to drugs/devices/therapies. Clinical researchers can not and do not ignore placebo/nocebo effects, but their operating principles have to rely on genetic/metabolic/pharmacodynamic/pharmacokinetic data, since those are clinically measurable. Unlike thoughts and (to some extent) feelings. The disconnect between the two is the basis of mandating PROs (Patient Reported Outcomes) and HRQoL (Health-Related Quality of Life) reports to be regularly gathered from clinical trial participants:
https://en.m.wikipedia.org/wiki/Patient-reported_outcome
https://en.m.wikipedia.org/wiki/Quality_of_life_(healthcare)
slouchingtoepiphany t1_isd34co wrote
You're absolutely correct, I work in clinical research and studies are often double-blinded, so we don't know who receives active treatment and who receives placebo. If any adverse events (AEs) occur, we record the information and later, when the study is unblinded and the data are analyzed, that's when we know if the study drug causes any AEs more than placebo.
Ganymede25 t1_isd7j0z wrote
That is interesting. I was in the Pfizer trial. When they unblinded us, the nurse that was giving us the results asked if we thought we had received the real thing or saline. At the time, she said that the participants were 100% correct. I don't know if that was an official question for the trial, but I think she just wanted to know if the guesses were correct.
slouchingtoepiphany t1_isd8rzm wrote
I don't see how participants could have guessed correctly, unless everybody thought that they received the actual vaccine. In that case, the people who received active treatment were 100% correct and the people who received placebo were 100% wrong. Hmmm.
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.
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.
eltrebek t1_isdsqy0 wrote
Adverse effects with placebo tend to range from 1-10% when reported in approved drug package inserts. I don't know why adverse effects to placebo are individually in the minority, but it does suggest that at baseline, this isn't an effect that guarantees a poor outcome.
Glad you had an uneventful reaction to your jab despite expectations <3
International_Bet_91 t1_isfbzcc wrote
The majority of side effects of the Covid vaccine are thought to be nocebo.
This article in Nature says 76%
People who haven't heard that there are side effects to vaccines, don't experience side-effects. İn my opinion, that means we should stop posting on social media about how we were in bed for 2 days after the vaccine.
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