Vinay Prasad's Observations and Thoughts

Vinay Prasad's Observations and Thoughts

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Vinay Prasad's Observations and Thoughts
Vinay Prasad's Observations and Thoughts
The CDC's MMWR only published observational mask studies - they often reached inappropriate conclusions - they published ZERO randomized studies on masks
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The CDC's MMWR only published observational mask studies - they often reached inappropriate conclusions - they published ZERO randomized studies on masks

The journal appears more interested in supporting political preferences that pursuing scientific truth

Vinay Prasad's avatar
Vinay Prasad
Jul 14, 2023
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Vinay Prasad's Observations and Thoughts
Vinay Prasad's Observations and Thoughts
The CDC's MMWR only published observational mask studies - they often reached inappropriate conclusions - they published ZERO randomized studies on masks
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In a new preprint out now from our team, we walk back memory lane and examine all the papers on masking in the CDC’s own journal MMWR. Do they represent good and reliable science? Or were they selectively chosen to support non-evidence based policies.

We searched all years of MMWR from 1978 to 2023, and found 77 studies pertaining to masks. All were from 2020-present. We asked a series of questions, and coded the answer in the figure. Tall green bars and short red bars is good. Sadly, you see the opposite.

First, we find many studies about masks did not actually study masks (~70%). Masks were one part of a broad set of policies, yet the MMWR authors made a claim about masks— essentially with no comparison. This is fundamentally illogical and unscientific.

Second, most studies 58/77 (75.3%) stated masks were effective. Of these 58 studies, 41/58 (70.7%) used causal language and 40/58 (69.0%) used causal language inappropriately.

Third, 4/77 (5.2%) had a numerically higher number of cases in the mask group than the comparator group but all 4/4 (100%) concluded masks were effective.

Fourth, and here is the key point: No studies (0/77; 0%) were randomized. Moreover, the authors did not even pubmed the randomized trials on the topic. Of all publications included, 0/77 (0.0%) cited a randomized study or review of only randomized studies.

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