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Further comments on “Assessing mandatory stay‐at‐home and business closure effects on the spread of COVID‐19”

A few weeks ago we discussed a recent paper from Bendavid et al., “Assessing mandatory stay‐at‐home and business closure effects on the spread of COVID‐19.”

Lonni Besançon writes:

Together with Gideon Meyerowitz-Katz we found that the study was fairly limited and did not properly highlight its limitations nor did it discuss several conflicting results from past work. We posted our concerns on PubPeer and we thought that you might be interested in these and that your readers might want to chime in.

Unrelatedly, he writes:

You might remember that I [Besançon] contacted you about our paper “Open Science Saves Lives” and a call for co-signature. I just wanted to let you know how it went. We have collected 371 verified signatures on our call for more transparency and on our analysis of the lack of transparency in COVID19 papers which is not too bad I guess. Based on all the comments we obtained we created a second version of the paper as a preprint and this is now under review.


  1. Anoneuoid says:

    One problem is the outcome measure. A decline in overall virus cases can also conceal increasing numbers of outbreaks and community spread involving variants.

  2. Bobby says:

    Mixed feelings about their review…

    Yeah some of their points are *obviously* true, but other points just don’t make any sense. Not the best, and definitely not the most fair review I’ve seen about this paper.

  3. Anoneuoid says:

    Off topic:

    This study reported 5.5 days to primary endpoint in the vitamin c group vs 6.7 in standard of care. That means recovering one day earlier on average, something the original study was powered at 80% to detect. The actually performed study was stopped early with less than half the expected sample size:

    Due to slower than expected enrollment, an interim analysis was conducted at approximately 40% of expected enrollment (214 of 520 patients).


    We assumed that the usual care group would achieve a 50% reduction in symptom severity in a mean (SD) of 6 (3) days and that at least 1 of the other 3 study groups would achieve a 50% reduction in a mean (SD) of 5 (3) days. Assuming a sample size in each of the 4 groups of 130 patients, a 1-way analysis of variance would have 80% power (2-sided α of .05) to detect a difference in means of 1 day with a common SD of 3 days.

    When will researchers be held accountable for making stats 101 errors like concluding no benefit from this type of study?

    Despite the popular use of vitamin C and zinc to fight off or lessen the severity of viral colds and flu, the new study, published Friday in JAMA Network Open, found the two supplements were of no benefit to people isolating at home with Covid-19. In fact, the findings were so unimpressive that the study was stopped early. “Unfortunately, these 2 supplements failed to live up to their hype,” wrote Dr. Erin Michos of John Hopkins and Houston Methodist’s Dr. Miguel Cainzos-Achirica, in an accompanying editorial.

    It is clear these people don’t have slightest clue what their results mean or the purpose of the steps they performed. Why are they being paid for this and held up as experts?

  4. Joshua says:

    Peer-reviewed critique of the study:

    From a summary of criticisms:

    > 4/ The analysis does not correct for the relationship between interventions and case counts.

    IMO, so totally obvious, it’s really shocking that it got past the authors.

    Clearly, the precipitating conditions would predict the severity of the interventions (on average) and also the kinds of outcomes independent, to some degree, of the efficacy of the interventions. To not control for that is mind-blowing – especially given Ioannidis’ stature as an epidemiologist.

      • Hi Joshua and thanks for pointing out to our letter and the twitter thread about it.

        There are so many things that are absolutely mind-blowing about the limitations of the study and the fact that many of them are not even mentioned (+ the very strong conclusions of the article).

        What is actually really problematic is that Ioannidis’ name is used to erase/destroy all possible criticism of the study. Many people online have pointed out that our letter has 0 value because we are not as good as he is… Can’t care much about this TBF but this goes to show that this article of theirs will be used no matter how valid our critics are (last time I checked their article had been shared 27k times on twitter only).

        I do not know if Bendavid et al. are ever going to reply to our letter. I certainly hope so, but I somehow do not see that happening.

    • Bobby says:

      Correcting for the relationship between interventions and case counts is basically correcting for the effect you’re looking for.

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