The test accuracy of the WHO test as far as I understood it was good if someone was already experiencing symptoms once viral load was high enough. The bigger is

The test accuracy of the WHO test as far as I understood it was good if someone was already experiencing symptoms once viral load was high enough. The bigger issue was false negatives, people would get released from quarantine measures, then spread it (like the cruise ship). They recommended anyone within contact to self quarantine until symptoms had reached a point they could get a definitive test. At this point testing early and coming up negative doesn't mean anything, you should still stay quarantined and continuously get retested, since a lot of people who tested negative were found to have had it the whole time when symptoms present and were given the all clear before. In summary, the testing early doesn't change the decision tree, which is stay quarantined for 14 days, until symptoms present or not, so little point was seen to testing until then. Problem is now, we can't track it, so everyone ideally should self quarantine or limit as much as possible social interaction and get tested if they have good reason to believe they've been exposed. Early testing will catch a lot of people but not all, so it will slow the spread, so at this point the decision tree changes and we need to start testing more, if nothing else to get a sample to extrapolate the true spread of this thing.