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A thought experiment.
Suppose we had a COVID test that had a 50/50 chance of identifying someone who was infected. And now imagine that everyone in a city uses this test. We identify 50% of the cases but miss the other 50%.
We repeat this a week later. Find 50%, miss 50%. 1/
Suppose we had a COVID test that had a 50/50 chance of identifying someone who was infected. And now imagine that everyone in a city uses this test. We identify 50% of the cases but miss the other 50%.
We repeat this a week later. Find 50%, miss 50%. 1/
If we repeat this process, over the course of a few months, we will have missed a lot of infections!
BUT, we will ALSO have identified enough infections, and broken enough transmission chains, to reduce viral spread.
The key? The 50% filter gets used over and over. 2/
BUT, we will ALSO have identified enough infections, and broken enough transmission chains, to reduce viral spread.
The key? The 50% filter gets used over and over. 2/
The idea of using repeated rapid antigen tests is like this, except that that 50 catch / 50 miss number is even better. Depending on the test, and where you draw the line, it could be 70/30, 90/10, or better.
So if we 90/10 every week for a few weeks, this has big impacts. 3/
So if we 90/10 every week for a few weeks, this has big impacts. 3/
The core concept behind repeated screening tests is that EVEN IF a test's sensitivity isn't perfect, its repeated use will drive the epidemic down.
Think about it: why do we complete a course of antibiotics? Because we clear that infection with repeated doses—not just one. 4/4
Think about it: why do we complete a course of antibiotics? Because we clear that infection with repeated doses—not just one. 4/4
