Schools + comments on some sources (THREAD)

This recent schools article makes some great points, and @apoorva_nyc is one of the top science journos on covid out there, but a few of the sources cited in this one have some issues, especially a few pages from govt websites. 1/22 https://twitter.com/apoorva_nyc/status/1319408652311285761

-UK link is outdated. For late Oct, random sampling estimates all 3 child age-groups more infected than any adult group. 2-11s are 2nd highest!

-The Netherlands govt website badly mischaracterises its study.

-Pediatrics childcare-worker study and NYC article need comment. 2/22

UK schools opened at start of September. No remote school, even for families with medical vulnerability. No temporary home schooling either.

The article’s linked UK govt webpage shows Sept infection for secondary-school and for primary-school and a few other groups. 3/22

EXCEPT these graphs are outdated and later required serious revision.

As @ChrisGiles_ demonstrates, ONS modelling has a track record of underestimating growth for the end of the time period shown, and then later revising. See especially the green late-September dip. 4/22 https://twitter.com/chrisgiles_/status/1319620517796741120

. @IndependentSage graphed the latest ONS random-sampling results. Spreadsheet says by 16 Oct, the 4 highest-infection age groups were

16-24-yr-olds (2.05%), 2-11-yrs (.79%), 11-16-yrs (.66%), and 50-69-yrs (.63%).

Ie, 2-11’s 25% higher than the highest all-adult bucket! 5/22

Yes, ONS previously underestimated infection for final weeks, but prior underestimates were fairly uniform across age groups.

This large-N random sampling also reveals that UK symptom-based PCR testing has substantially under-reported child infection, relative to adults. 6/22

Why 2-11 > 11-16? Primary students get many colds. Avoiding testing cold-like symptoms and asymptomatic kids means many cases missed.

More 11-16 cases found with PCR. Many secondary schools home-isolated whole yr groups. Also, MASKS: many UK primary schools *forbid* masks. 7/22 https://twitter.com/sarahdrasmussen/status/1309437278218006528

Kids dominating infection isn’t just a UK thing. It appears to be a “wide-spread testing in context of circulating kids” thing. Like Isreal’s Health ministry’s recent findings.

TOI says was based on >2 million tests, for a population of <9 million.
https://www.timesofisrael.com/health-ministry-report-finds-kids-more-likely-to-catch-virus-than-adults/ 8/22

Next source: Netherlands govt webpage.

This page totally mischaracterises a small sample-size 54-household study of families of covid-infected patients.

In the actual study, 12-17-yr-old household contacts had a *higher* infection rate (34%) than 18-45-yr-olds (28%). 9/22

Total 18+ rate: (10+13/36+31)=34%, same as 12-17.

The only groups with new +ive PCR tests at 2-3 weeks were 1-5- and 6-11-yr-olds, with 1 new case each, totaling to 16% and 18%.

So overall, the 3 child hh contact grps had 57%, 64%, and 121% the infection rate of 18-45s. 10/22

Next source: Pediatrics study on US childcare workers for mostly <6s.

This was a much better source: large sample size, good collection of contextual data...

But they failed to ask workers the most important question: what did you do for income if your center closed? 11/22

Because unlike school teaching, infant childcare cannot be done remotely, and *many* childcare workers don’t have enough savings to go months with no income.

So what did they do instead for money—individual childcare in less regimented settings, food delivery?, what? 12/22

With P<.01, home-based childcare workers had a 59% higher infection risk than non-home-based. This notably was independent of whether officially required to be closed.

Home-based workers would likely have an easier time arranging unofficial childcare work for themselves. 13/22

There were also paradoxical effects.

More masks/hand-washing/social-distancing in public meant a *higher* infection rate (OR 1.16, P=.24).

Granted P=.24, but for P=.001, avoiding friends + extended family, and (especially) avoiding eating out, meant 27% more infection. 14/22

To explain this, authors guessed maybe higher vigilance occurred in higher-covid areas.

OTOH, maybe workers used more masks etc if forced to *work* in exposed settings. Less eating out could also have correlated with more financial vulnerability and greater need to work. 15/22

Valid comparisons require knowing what the control group did.

All this study shows is that whatever childcare workers did *after* they lost their official childcare job, that provided comparable infection exposure to what open childcare centers provided for other workers. 16/22

Next up: the NYC schools article.

Whereas the article reports 378 school cases found by targeted testing, random sampling of 16.3K staff and students found 28 cases.

BUT: what matters is how that compares to *community* levels. https://www.nytimes.com/2020/10/19/nyregion/schools-coronavirus.html 17/22

Random sampling for the school week from 9 Oct (9+13-16, schools closed on 12th) found 28 cases out of 16.3K tests, or .17%.

Avg +ive targeted PCR tests for NYC then was 461/8.4 mil/day, or .038% +’s/pers/week.

To compare, we must rescale the latter % for missed cases. 18/22

In the UK that week, that rescale factor was .79%/.17% = 4.6. For NYC, that gives .038% x 4.6=.17%.

But UK has higher infection and only tests symptomatic. NYC tests anyone who wants, for free. So NYC likely <.17%. Just hard to guess how much less. NYC schools were .17%. 19/22

Back to @apoorva_nyc’s article.

It made some great points, like how in Sweden, upper secondary schools closed in spring, and those remote teachers had median levels of infection. But teachers for lower secondaries (all in-person) were among the most-infected professions. 20/22

On the flip side, Boston recently stopped in-person schooling even for severely-disabled and highly socially vulnerable children.

That’s utterly ridiculous.

Surely they can find enough high-quality PPE and ventilated space to teach this tiny group.
https://www.boston.com/news/education/2020/10/21/boston-public-schools-suspending-all-in-person-learning 21/22

This isn’t some all-or-nothing tug-of-war with winners and losers.

This is a world of communities with different infection levels, different cultures, different resources, and different individual needs.

Getting the balance right is hard.

It will take the best we can do. 22/22