Thread by @apsmunro

I have seen some repeated assertions about the evidence on #COVID19, children and schools recently which sound convincing, but unfortunately are false

It is a sensitive and important topic, which is important to get right

Shall we bust some myths? 💥

Let's go!

1/10

Myth 1. Evidence suggesting limited transmission within schools is based on flawed evidence as only children with symptoms were tested ❌

There are many studies drawn on symptom based testing, there are MANY which are not, and all find the same thing

Here's just a few...

2/10

Australia
thelancet.com/journals/lanch…

Norway
eurosurveillance.org/content/10.280…

Italy
eurosurveillance.org/content/10.280…

Hong Kong
eurosurveillance.org/content/10.280…

Germany
medrxiv.org/content/10.110…

Switzerland
medrxiv.org/content/10.110…

3/10

Myth 2. Long COVID affects 13% of infected children ❌

This is based on an incorrect interpretation of some ONS based data on symptoms in children, with NO control group

For why this is a *major issue*, read this excellent article

bmj.com/content/372/bm…

4/10

We certainly need more data on long covid in children (studies are underway), but given infection in children is predominantly mild or asymptomatic, prolonged, severe symptoms are unlikely to be common

5/10

Myth 3. International modelling shows schools drive transmission, and are less biased

That was not the finding of this systematic review of these studies

6/10

https://twitter.com/apsmunro/status/1355939249334448130?s=20

Nor was it the finding of this modelling study from the US which determined children played a relatively minor role and young adults were the driving factor (which is what has been observed internationally)

5/10

https://twitter.com/apsmunro/status/1357359671447805953?s=20

Models have their uses, but are subject to the limitations of the data and assumptions put into them

Modelling of school closures relies heavily on data from Spring 2020, when accompanied by near simultaneous implementation of other interventions. This bias is baked in.

6/10

Myth 4. Primary schools play just as important a role in transmission as secondary

I've heard people quote the number of outbreaks being the same from PHE data as evidence

Not untrue, but ignores the fact there are nearly FIVE TIMES MORE primary than secondary schools

7/10

Not only this, but data from a survey from the first half term in autumn showed the *majority* of cases in primary school outbreaks were in staff, not children

Also, random, in school sampling by ONS found lower prevalence in primary than secondary schools

8/10

Does this mean transmission doesn't happen in schools? No

Does it mean we can open schools willy nilly? No

Does it mean the consensus of the EU and US CDC that transmission within schools is relatively low and not the driving factor in community transmission is sound? Yes

9/10

For the excellent review document from @ECDC_EU see link

ecdc.europa.eu/en/publication…

And from @CDCgov see link

jamanetwork.com/journals/jama/…

Myths busted!

10/10