[denysonique]

What if it is not melatonin itself, but the fact that it helps to get more sleep which generally boosts the immune system and has anti-inflamatory effects.

Sleep length/quality should have been taken into account.

Have scientists rediscovered the importance of sleep?

[TrevorJ]

This is, of course, the right question to ask. The good thing is, we can still reasonably act on this data while we wait for more studies to disentangle the cause/correlation relationship. Melatonin is well tolerated, and also produced endogenously, so the risk/reward on this treatment is in our favor.

[dangom]

Well, we could turn your question around. What if it is not sleep itself, but the fact that it is related to the release of melatonin which potentially mediates immune system responses and inflammation?

The paper offers interesting hypothesis into why this could be the case.

[smt88]

The study is of intubated patients, I think they're asleep a lot...

But I'm sure poor sleep habits are a risk factor for severe Covid anyway.

[nikolay]

And that's not what melatonin does.