China tested all 11M Wuhan residents in a week

Does anyone have any details about how they were tested?

It’s actually easier to test at scale when infections are rare: If you only expect something like 0.001% of tests to be positive, you can start combining 1000s of samples into batches to test at once, only narrowing into individual tests if a batch shows positive results.

This can shave orders of magnitude off of the number of tests that need to be run. Of course, actually collecting samples from 11M people in a week (if we are to believe the government-provided statistics) is still a massive logistical achievement.

> It’s actually easier to test at scale when infections are rare: Perhaps they began by testing the sewer water?