Thread by @apsmunro

With so much attention on #COVID19 in children, time for an updated #tweetorial on what we do and don't know!

We'll talk impact, risk, hyperinflammation syndrome, transmission, schools and more

Lets go!

1/21

Children remain grossly underrepresented in all case numbers, hospital admissions and deaths worldwide

See latest ISARIC report of >15,000 severe cases, or @PHE_uk UK deaths

media.tghn.org/medialibrary/2…

publichealthmatters.blog.gov.uk/2020/04/23/cor…

2/21

This report from @sunilbhop and friends looks at child deaths from #COVID19 compared to other causes to put them in perspective

Of ~37,000 child deaths, 43 were from COVID19

In the words of @d_spiegel , children are "unbelievably low risk"

3/21

https://twitter.com/sunilbhop/status/1262315964898697217?s=20

Are some children higher risk?

Small numbers, but children usually at risk from viral respiratory infections look equally at risk from #COVID19, including tech dependent, neurodisability, malignancy or chronic lung disease

jamanetwork.com/journals/jamap…

jpeds.com/article/S0022-…

4/21

Important to note outcomes still pretty good for these groups, and there a number of documented cases for some (e.g. oncology, immunosuppressed) which had a predominantly mild clinical course

Even most of these children don't get very sick

jamanetwork.com/journals/jamao…

5/21

What about this hyperinflammatory syndrome?

It's called PIMS-TS (or MIS-C in the USA)

It seems to be an immune reaction after COVID19 infection (approx 2 - 4 weeks)

Usually starts with persistent fever, abdo pain and D&V, then can present similar to Kawasakis (+/- shock)

6/21

We currently have 3 published cohorts from London, Italy and France

Many kids get very sick, but most recover well

It seems to be dissipating (following trends in peaks of infection)

Read more about it here

dontforgetthebubbles.com/pims-ts/

7/21

It can be serious, but is incredibly rare

In Europe there have been about 230 cases and very few deaths. There are >80 million children

Europe CDC considers it a low risk. Be reassured

ecdc.europa.eu/sites/default/…

8/21

OK - transmission. Let's go step by step.

How easily to children catch it?

5 studies have looked at transmission to children (mainly household) and 4/5 found *significantly lower* attack rates in children than adults

dontforgetthebubbles.com/the-missing-li…

9/21

How many children actually have/had COVID19?

<2% of known cases have been in children, but given symptoms are so mild have we just missed them all? Are they mainly asymptomatic? Are they silent assassins?

This is harder to tell, but there is some evidence...

10/21

Iceland tested those at risk and found 1/2 rate of infection in children <10y compared to adults, and 0 cases in asymptomatic screening

nejm.org/doi/full/10.10…

Vo, Italy screened >85% of the population. 2.6% had COVID19, but 0 children <10y

medrxiv.org/content/10.110…

11/21

Some say ONS data shows there's no difference between children and adult infection rates

But they found ~30 positive cases in 10,000 people

The CIs are too wide for inference about relative infection rates (compatible with 10x rates in any group)

ons.gov.uk/peoplepopulati…

12/21

The same principle applies for 2 sero-epi studies from Switzerland & Germany

Despite lower rates of infection in children, numbers too small to be statistically significant

This is not evidence for equal rates of infection

medrxiv.org/content/10.110…
medrxiv.org/content/10.110…

13/21

What do we find if we do proper sized sero-epi?

Infection rates of 1-3% in children compared to 5% in adults in a Spanish study of >60,000 people

ciencia.gob.es/stfls/MICINN/M…

14/21

How infectious are children when infected?

Hard to say. Some examples of children not spreading at all despite multiple exposures (>100 other children) but spreading other respiratory viruses

academic.oup.com/cid/advance-ar…

15/21

A German study claimed to find similar viral loads in children as adults, stating they're "just as infectious"

zoonosen.charite.de/fileadmin/user…

Amongst other issues, if analysed properly the data actually showed significantly lower viral loads in children

osf.io/bkuar/

16/21

National reports from Netherlands
rivm.nl/en/novel-coron…

Iceland
eapaediatrics.eu/eap-blog-covid…

Norway
fhi.no/contentassets/…

Australia
ncirs.org.au/sites/default/…

Have found limited evidence of children contributing to spread of COVID19. Most transmission is adult to adult.

17/21

What does it mean for schools?

adc.bmj.com/content/early/…

Children can get COVID19 so can almost certainly spread it

But, they are barely affected by infection, and appear less likely to catch or spread it than adults

Schools seem lower risk than adult work environments

18/21

Will outbreaks happen? Of course.

But this is our new reality for the foreseeable future. We need to mitigate against the risks and ensure mechanisms for quick response (track/trace/isolate) are in place

Children suffer harm from lockdown

bmjpaedsopen.bmj.com/content/4/1/e0…

19/21

Now for WHY children seem so much less affected...

Still no clear answers. Possible differences in ACE2 expression, but they seem small

jamanetwork.com/journals/jama/…

Some suggest immune differences. Need to be proven.

thelancet.com/journals/lanch…

More research needed...!

20/21

Thanks for making it to the end!

For our comprehensive review of all paediatric #COVID19 literature (cited by @UKRI_News and @WHO ) check it out here on @DFTBubbles

dontforgetthebubbles.com/evidence-summa…

21/21