Thread by @apsmunro

The #SARSCoV2 variant b.1.1.7 is taking over

But is this variant especially scary in children? ☠️

Are they suddenly driving infections? 🚗

Is this quadruple worrisome? 😱🚨⚠️

Let's take a look at the evidence

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b.1.1.7 became of concern initially following a surge of cases in SE England after autumn lockdown

Case trends in children had previously lagged adults by a week or so (because adults drive infection rates), but this surge happened near simultaneously

doi.org/10.1016/j.jinf…

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Some scientists leaked to the press of "hints" that there was something unique to children about this variant

This was based on an increased share of b.1.1.7 cases in children compared to adults during the late Autumn

doi.org/10.1101/2020.1…

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However, later analysis showed this was an artefact of the fact that whilst the variant case share increased, schools were essentially the only thing opened

Over time this levelled out. It was just a blip in time.

science.sciencemag.org/content/early/…

4

This was confirmed by contact tracing data looking at secondary infections by age

It showed the same age related differences in susceptibility (younger children less susceptible) - but that all ages appeared more susceptible than to ancestral strains

assets.publishing.service.gov.uk/government/upl…

5

What about scary things happening in other countries?

Well, Denmark famously has a lot of b.1.1.7 (they are good at sequencing)

What's going on in Denmark? 🇩🇰

covid19genomics.dk/statistics

6

Well, case rates are looking pretty much unchanged since January

Whilst primary school aged children are in school full time, with no masks on...

covid19.ssi.dk/analyser-og-pr…

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But was there a study of 3 MILLION people from Denmark showing children at home increased risk of infection?

Yes, but 2 important points:

1. *Anyone* at home who goes outside and mixes will likely increase risk
2. Observational studies are difficult

medrxiv.org/content/10.110…

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For example, a study in Scotland looking at almost exactly the same thing found the complete opposite results

Which one is true? Possible either, possibly neither.

Just because there are lots of people in your data can't undo baked in confounding

medrxiv.org/content/10.110…

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But aren't children super infectious silent spreaders who are driving infection?

Well Denmark have conducted another data linkage study on household infection which would suggest not...

doi.org/10.1101/2021.0…

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In keeping with other household contact tracing studies, children appear less susceptible to infection

Attack rate in <10yrs 31%

Attack rate in 25 - 45yrs 52%

But that's not all...

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Children <20years were the least likely to transmit to others in the household

Interesting downward slope from young children to the 20yr olds, but this seems mostly an affect of youngest children having high exposure to very susceptible grandparents

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There is some preliminary evidence of more severe illness in adults (based on community cases)

But is disease with b.1.1.7 more severe in children?

What about the hospital wards supposedly filling up with sick children in London in the autumn?

doi.org/10.1136/bmj.n5…

13

Well we can see from this data that more kids were in hospital, but they were way less sick than during the first wave

In fact, A THIRD were incidentally found to be infected (i.e. admitted for something completely different)

doi.org/10.1016/S2352-…

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So, b.1.1.7 in children isn't quite so scary after all

It seems to be a more transmissible variant, but no different for children than adults

Denmark has kept schools open for young kids (even without masks) and hasn't exploded

Add in vaccines, and maybe we will be OK 👌

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Addendum:

Newspaper reports are not evidence. Treat them with utmost scepticism pending scientific clarification

For the actual scientific evidence about COVID in children from the beginning, it's all reviewed right here!

dontforgetthebubbles.com/evidence-summa…