Even tiny sensitivity would be better than nothing – or something that's so slow & expensive it's impractical.
But other antigen tests purport to have 90%+ sensitivity.
And the kinds of "PCR positives" they miss are often cases that are no longer infectious, anyway: lingering viral fragments, rather than live full-virus shedding.
So: ideal for border-control & creating other internal gradients that help suppress the worst active cases. The perfect should not be the enemy of the very good.
> Even tiny sensitivity would be better than nothing
Not if you imagine that one case on a plane = potential super-spreading event, the plane touches down and then newly infected people go in every direction.
Your hypothetical test with tiny sensitivity is pointless, in this regard: it has a (less than) tiny chance of preventing each risky passenger. In my view, any kind of low-sensitivity testing before departure is theatre: it won't make any difference in preventing new infection from breaking out.
The government of the country that I am in agrees, and requires a negative PCR test.
But other antigen tests purport to have 90%+ sensitivity.
And the kinds of "PCR positives" they miss are often cases that are no longer infectious, anyway: lingering viral fragments, rather than live full-virus shedding.
So: ideal for border-control & creating other internal gradients that help suppress the worst active cases. The perfect should not be the enemy of the very good.