Thread by @michaelmina_lab

This is one of the most rationally written papers yet on #rapidtests to keep society running, shops open, people dancing and curb transmission

It also demonstrates well the problems of using high sensitivity lab testing for public health screening.

thelancet.com/journals/lanin…

The paper shows 500 ppl who went to a concert and were rapid tested before hand.

They also received super high sensitivity molecular lab tests before as well - but the results arrived only after the event.

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What they found was interesting.

First - no one turned up positive on the rapid test at the outset. So a strong evaluation of its ability to screen ppl out didn’t really happen. But that’s ok, we already know the test sensitivity.

What is much more interesting...

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Is that there were about 3% (~15) people who entered into the dance hall, were negative on the rapid test but were later found to have been positive during the event based on the high sensitivity molecular lab test results returned later.

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Despite them entering and dancing the day away with positive results on a lab based molecular test but negative rapid Ag test - no transmission occurred!

Why??

Simple... the negative rapid tests were the CORRECT result for the ?

“Am I safe to enter and not transmissible?”
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Although the high sensitivity lab based tests were positive - all of the people were already post-infectious. Some over their contagious period for many weeks already.

Calling them positive would have been effectively false positives as far as public health is concerned.

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None of the samples that were positive on the lab-based molecular test but negative on the rapid Ag test were able to be cultured and none showed evidence of being infectious and indeed, none led to infections at the close encounter event.

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In short, this study demonstrates well that a) entrance screening before an event can facilitate the event w/out superspreading or transmission and b) that we should be VERY careful about how we are comparing rapid tests to high sensitivity lab based tests.

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We MUST define WHY we are performing a test before determining the comparison

As far as the regulatory agencies are concerned, those rapid Ag tests were false negatives... but NO... the lab tests were false positives as far as needing isolation is concerned.

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Tests have different meaning and different purposes. Regulatory agencies like the @US_FDA and public health bodies like @CDCgov have almost entirely failed to appreciate the differences.

The result has been 100,000’s excess deaths due to failures to authorize these tools

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Hopefully the future will be brighter for science and nuance to enter into our public health decision making. But I’m not holding my breath. The road to get the tests authorized at all has been horrid. Our agencies need complete overhauls.

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We wrote about the differences in the types of testing here w @K_G_Andersen

science.sciencemag.org/content/371/65…

This paper being discussed in this thread was authored by @RevolloBoris and colleagues.