Charles R. Twardy

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Estrogen, COVID-19, and Rapid Reviews

In my day, philosophers encountered birth control pills at least twice during training. First and easiest, your account of causation could not simply say birth control pills reduce the chance of pregnancy - they have no effect on men’s chance. Second, and trickier, how to handle their effect on blood clots? By simulating pregnancy, they increase the risk of clots. But by preventing pregnancy they decrease it. Once, you could publish papers about that.

Well, here they are again. MIT Press has a new journal devoted entirely to rapid reviews of COVID-19 papers. (Hopkins does too.) And by way of introducing them, their most recent reviews.

This study on estrogen got two strong reviews. Women are less susceptible than men to C19.* Estrogen is one possibility. The authors confirm that post-menopausal women had worse symptoms, but then age is an even stronger risk factor.

However, thanks to medicine apparently invented to confound philosophers, it’s possible to separate estrogen from age. Among pre-menopausal women, those on oral contraceptives appear to have fared better. (This was not clear for older women on hormone replacement.) The study has some limits - it’s not a randomized trial.

But once again causal analysis of pills and blood clots is relevant, and here the pill itself provides a quasi-intervention. Causal payback, baby.

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  • It was tempting to write “Women are less susceptible to C19 than men.” The ambiguity is delightful, and one wonders if it is true.