It honestly seems borderline unethical to give people a placebo vaccine.
https://www.statnews.com/2020/09/03/placebos-arent-needed-ch...
Also, there is a very strong risk, given the global situation, that the longer placebo-controlled trials go on, the less reliable the data will be, because control-group subjects will ignore the rules of the study and go get vaccinated as soon as it's broadly available just in case. So even just looking at data quality and excluding other considerations, placebos have major risks that probably outweigh the benefits of administering them for months or years like a usual vaccine trial would.
It's only unethical to withhold the vaccine if you know that it's safe and effective. The whole point of the study is to figure out if that's the case. It's possible for vaccine candidates to be ineffective, or even harmful (e.g., antibody-dependent enhancement).
The inactivated polio vaccine, for example, does not prevent infection. It just prevents disease. That means that it cannot confer herd immunity (vaccinated people can act as asymptomatic carriers, leaving unvaccinated people at risk), but for most people who are vaccinated, it eliminates the most serious consequence of polio infection - paralysis. The SARS-CoV-2 vaccines might end up being the same, conferring protection from disease but not from infection, and even that would be important.
Without a placebo group, how will you measure effectiveness and safety? You need to monitor a statistically equivalent group of people to determine the difference in rates of infection and disease, and to look for side-effects.
> Would the researchers not want people to go out and live their normal lives?
That would be great for the trials (assuming both the vaccinated and placebo groups behaved identically). But most people would consider it unethical for researchers to encourage the trial participants to increase their likelihood of exposure to the virus. People who sign up for vaccine trials are not signing up to get CoVID-19.
It’s spreading like wildfire to people following best practices too all over the world. It only takes a small subset not following these practices to spread it all over.
You may still have increased risk taking behavior if you don't tell them whether they got the real vaccine or placebo, but it will be equally increased across the experiment and control groups.
Really it's about measuring how likely vaccinated participants are to contracting the virus than those that received the placebo.
A real vaccine, with side effects that are similar to what is expected of the covid-19 vaccine. It is a well tested and safe vaccine and it will protect you from meningitis but not from covid-19.
They are doing that exactly for the reason you are mentioning. Of course, participants are aware of the nature of the placebo they might receive.
wtf?! a placebo should by definition have no effect at all
In fact, there are even placebo surgeries. They put you to sleep, cut you open, and stitch you back without actually doing anything inside your body. It is far from nothing, the anesthesia and the incision are real. It is important because you want to compare the effect of the actual operation to everything else that is involved in a surgical procedure.
Having them expose themselves more to the virus is a "good thing" (though tell them how long should they wait for the immunity to set in)
Yes, with the control group you would have a base for how many people you would have expected to be infected, so there's that, but you "could" get that from other observations
Getting this number for a distribution of people as similar as possible to the people in the experimental group is, in fact, the primary purpose of having a control group. There is no better way to predict this number, as you can't predict how likely a particular person is to catch coronavirus at a particular time, in a particular location.
You also need a control group to get the number of various medical problems expected in the experimental group, even if the vaccine doesn't cause them. This also depends on time, place, and behavior.
So, if you create a reason for people in the control group to behave differently from experimental group, for instance by letting people find out which group they are in, you defeat the purpose of having a control group.
I'm not denying there's the need for a baseline to compare to, but the need to have an dedicated designated group to be the 'official control'. I agree it makes things easier statistically.
> So, if you create a reason for people in the control group to behave differently from experimental group
Yes and here lies a minor catch, both those groups might behave differently from the population in general (even though they aren't "supposed to")
No, if they change their behavior, you couldn't.
Why are so many people commenting when they clearly don't understand knowledge-creation/statistics/methodology?
Because (a) we want to understand. and (b) reasonable experts differ on what constitutes proper methodology which is constantly being improved.
Surely the effect size of a useful vaccine is large enough that modified behaviour of the vaccinated does not matter at all. We're not looking for a small incremental improvement in contraction rate of the virus here, we're looking for a very large percentage of those who have been administered the vaccine not getting covid. Yeah it could change behaviour but so what? How is that going to bias the result to suggest it isn't working if it is? (or vice-versa)
You talk about knowledge-creation and answer with a dogmatic tautology.
Then people wonder why anti-scientific sentiment is at high levels...
Anti-scientific sentiment is at high levels because you don't get someone to personally explain basic statistical concepts that you could have googled yourself?
(Needless to say, running an invalid vaccine trial also has very bad consequences: it would delay the actual deployment of a working vaccine to the general public, resulting in millions of unnecessary person-hours of potential virus exposure.)