Thread by @covidtweets

After colleges began opening for in-person instruction, some useful data began emerging. Here is one from Duke University. Below is their cumulative testing and cases data since August 2nd. Look at that % positive: .13%. Lowest I have ever seen. Seems strange? (Thread/1)

Now let's look at how they do these tests: Self-administered nasal testing, which, according to at least one study, is almost as accurate as nasopharyngeal, when patients are obviously infected (symptomatic). So what is going on? (2/x)
upi.com/Health_News/20…

My theory: How often do we clean inside our noses vs. the uppermost part of the throat, behind the nose? Perhaps one is more likely to find inactive virus remnants via deep swabs, but as long as the virus is not active, there is no longer any RNA remaining inside the nose. (3/x)

If this is true, it would mean two things: 1) Many of the cases on other colleges which use deep swabs are false positives, since there is no reason their students would be different from those of Duke, and 2) Deep nasal swabs should be discontinued from being used. (4/x)

Now, a couple clarifications: First, it is not possible that this extremely low % positive is because Duke is managing really well, since their entry testing (they tested all students before moving in) also gave 24/8531 (.28%) positives. (5/x)

Second, this is clear evidence that these tests are effective in detecting when someone is infectious without all those false positives, given the lack of outbreaks in Duke. As a side benefit, they are less invasive, and less risky for healthcare workers. (6/6)