Thread by @apsmunro

A quick 🧵on testing kids for #SARSCoV2

Many people believe children are more likely to have false negative results to:
- antibodies tests, due to them having mild illness
- PCR tests, due to difficulty sampling

Turns out, that's almost never the case

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First, antibody tests

Most serology tests used in studies test for antibodies against the Spike protein (we call these S IgG)

This nice Australian study, found no difference in rates of children seroconverting to S IgG compared to adults

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wwwnc.cdc.gov/eid/article/27…

In fact, not only that - but this study shows younger children actually have HIGHER S IgG levels than adults!

Their super immune systems make a bangin' response

Good work kiddos

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sciencedirect.com/science/articl…

Some people may be confused by this paper, which showed children/young adults are less likely to be positive to Nucleocapsid antibodies (N IgG) than older adults (due to less severe illness)

Young children had higher levels of S IgG in this study too

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doi.org/10.1038/s41590…

There are several assays for N IgG, and it's useful for people who are vaccinated to see if they've been infected (current authorised vaccines will make you S IgG positive, but not N IgG positive), but it is by far the less commonly used assay

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Now for PCR!

Some people were concerned that because it is difficult to swab children, there might be lots of false negative tests

Now that we have some data, it looks like actually the opposite might be true...

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This study measured the amount of RNAseP alongside SARS-CoV-2 in kids and adults swabs

This checks for swab quality by looking at the amount of human cells you collected along the way

Children had MORE consistent samples than adults (less virus too)!

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journalofinfection.com/article/S0163-…

The explanation for this actually makes a lot of sense

Because we use the same size swab for kids and adults, but kids have smaller noses, the swab spends much more time in contact with the mucosal lining and picks up a better sample

The data backs this up

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As you can see, in the instances when we find less #COVID19 in children than adults, the evidence suggests this isn't meaningfully impacted by differences in performance of the test

Sometimes if you're looking for something but can't find it, it's just because it isn't there

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