I think that it's always possible to find lots of theoretical problems with case control studies, but they are well accepted in epidemiology. It is a very difficult thing. I also think the guy is being disingenuous in talking about randomized clinical trials because I think that is virtually impossible in this case. The idea of a randomized clinical trial is that some subjects are randomly assigned to the treatment and some are randomly assigned to the control group. And nobody knows which group they were assigned to.SeattleGriz wrote: ↑Mon Feb 07, 2022 8:34 pmThank you for the links. I don't doubt you've read the studies. You've got a lot of logs in the fire currently in this discussion, so I'll be quick. The guy below says the latest CDC study is really poor.JohnStOnge wrote: ↑Mon Feb 07, 2022 4:42 pm
SG, one thing you can count on is, if i say there are studies to support a point of view, I have looked at some studies like that. A couple i've looked at are at https://www.cdc.gov/mmwr/volumes/70/wr/mm7039e3.htm and https://jamanetwork.com/journals/jamane ... le/2781283. Here is one that just came out: https://www.cdc.gov/mmwr/volumes/71/wr/ ... mm7106e1_w.
Also, you can go to the CDC page at https://www.cdc.gov/coronavirus/2019-nc ... -cov2.html, read the discussion of a bunch of studies cited in support of their conclusions, and look up some of the 90 references they provide if you want to.
The actual epi studies are all observational so we say that they show association rather than confirming cause and effect. But it's a situation where that's what you have to do. We can't have controlled experiments on something like trying to get people to wear masks. We do have controlled experiments showing how masks do reduce the distribution fine droplets and aerosols.
I just saw a doctor on TV arguing against mask use because we don't have randomized experiments to show mask effects. We also don't have randomized experiments to show that smoking causes cancer in human beings. We say that it does because we have so much evidence of association plus some evidence of mechanisms involved. There are some situations where you have to go with observational data. And in a situation like this common sense should tell you that impeding the breath of infected people is going to reduce transmission risk.
This thing of saying that the science doesn't support something like masks in public school when a surge is going on is just wrong. It does. That is unless you take the approach of saying "yes it reduces the rate some but you also have to consider the psychological damage it does to kids." I wouldn't agree with saying it's a net negative based on that but at least it's an argument.
I don't have the skills to determine if he's right or not, but here's the link to his article on the study. You probably talk similar language.
https://vinayprasadmdmph.substack.com/p ... scientific
Vinay Prasad MD MPH is a hematologist-oncologist and Associate Professor in the Department of Epidemiology and Biostatistics at the University of California San Francisco. He runs the VKPrasad lab at UCSF, which studies cancer drugs, health policy, clinical trials and better decision making. He is author of over 300 academic articles, and the books Ending Medical Reversal (2015), and Malignant (2020).
So like with a vaccine, some subjects are randomly assigned to the treatment group that will receive the vaccine. Others are assigned to the control group that will receive the placebo. No member of either group knows which group they are in.
With masks, obviously, even if the treatment was wearing a mask there is no way people who were in the treatment group and the control group wouldn't know which group they are in. And the treatment isn't wearing a mask. Primarily, the treatment is defined by how many people around you are wearing a mask. So the treatment would be having everybody around each person in the treatment group wearing a mask at all times while the subject also wears a mask and the control group would be nobody around the person in the control group wearing a mask at all times and the control subject also not wearing a mask. It is an impossible experiment. Not going to happen. And you certainly couldn't have a situation where people in the treatment and control groups didn't know which group they were in.
To me, the fact that he makes a big deal about no randomized clinical trials means he's not writing in good faith.
That's literally the FDA approved Pfizer vaccine. It was called Pfizer-BioNTech COVID-19 Vaccine but is now marketed as Comirnaty since it's FDA Approved. 
