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No country has tried the test everyone strategy except as part of research. The reason is that it is unnecessary and it is expensive. The way NSW, the state I live in Australia, is working now is to test anyone who is admitted to hospital with a respiratory condition. They are also testing anyone with a respiratory symptoms that are in an area with unidentified transmission. Then for identified cases the contact tracing starts and anyone who has been in contact with a case is also tested. Given that our active cases out in the community are probably in the order or less than 5 per 10,000, testing of the asymptomatic population or even people with respiratory symptoms in many areas is not effective use of tests. One thing we haven't been doing enough of is convincing people with mild respiratory symptoms to self isolate, and if possible their households as well. It is cheap, and given the number of false negatives, almost as effective as testing. The advantage of testing is that it justifies contact tracing. When we have the testing capacity we should be doing everyone with respiratory symptoms.


Between when I wrote that article and today, the case has only strengthened. Evidence is piling up that one of the reasons why this novel coronavirus is so potent is that it spreads fast, and one key reason for the speed is the prevalence of silent carriers - people who do not show any symptoms but have high viral load. One of the gravest mistakes made here is testing only people with severe symptoms. We can't even diagnose the problem of silent carriers, let alone solve it. It's tragic.

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