Harlan Krumholz

If you look at everybody, then you might not find an effect.

But if you look at what's called the per protocol, the people who actually keep the mask on, you get these reductions, which are important reductions in slowing down the spread.

So I think it's interesting as well.

I mean, the Cochrane review is very interesting because I think it does guide what's going on here.

There are three important implications for practice that they highlight.

First is, as I've said, the frequent hand washing.

And they say with or without a junk antiseptic.

So it's OK to use soap.

So that's the first thing.

The second is barrier measures such as gloves, gowns and masks with filtration apparatus.

That's the sort of what you'll see in the hospitals when you've got everybody completely gowned up.

Now, altogether, that gets you about a 90% reduction, them two measures.

So that's why you'll see in the hospitals people taking a combination of them.

But the third one is with a suspicious diagnosis, isolation of likely cases.

And that's what we're seeing right now.

That can only work if you really put all three together and somehow we drive down the infection so it doesn't get out there in the public and particularly in children.

You said it's quite sparse and it's... Well, look, if this was a drug, we wouldn't be putting this into routine practice because the quality of the evidence here is very poor.

And I think it's because one of the things is we haven't really thought about this and probably till about 2009 with the swine flu epidemic that emerged, pandemic, sorry, that emerged.

And now it's becoming really important to understand some of these features.

And we have seen certain information and trials come out.