Thread by @apsmunro

New paper on #COVID19 contact tracing in the US, looking at household secondary attack rates (SAR)

doi.org/10.1093/cid/ci…

Abstract suggests equal SAR in children and adults - an unusual finding in these studies

As usual it's a bit more complicated than that...

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First an important point:

Do not group all participants <18y together

We've seen big differences in children <10y compared to 15y+ in many other studies

Of course, it is no different here

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What happens when we separate them out?

SAR 10 - 17y 58% (!)
SAR 0 - 10y 18% (!)

SAR for adults (spouses) 33%, so for young children a ratio ~ 0.5 - what we've seen in most other studies (inc. meta analyses

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Importantly, these results all include serology, so we know we're not just missing cases on rt-PCR

There were no significant differences found between pick up on PCR/Serology in adults vs children (but 4/18 were positive on serology only)

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What I cannot explain is the insanely high (by any standard) SAR for children aged 10 - 17y

I can't think of any biological/environmental factors which would account for this

Maybe a fluke, but if anyone has a look and has suggestions I'd love to hear them!

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Strangely the authors don't even mention this in their discussion

As usual, read beyond the headline and superficial analysis - especially when a new study has findings inconsistent with many that have come before it

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