Reports about COVID-19 testing in the U.S. seem to frame the number of tests performed as if once a person gets tested and learns their result (COVID-19 pos or neg), they can be filed under "tested" and they're done. This is bothering me. Here's why...

The test being used in the U.S. right now detects the presence of the virus nucleic acid in a person's body. This test will tell you if you're currently infected with SARS-CoV-2. Let's say you test negative. Great! That's a relief. You're not infected with the virus at this time

But this doesn't mean you can't be infected in the future. You're negative right now, but if you are exposed to the virus later, you may be infected & test positive. I'm concerned that we're presenting "number of negative tests" as absolutes, when it's just a snapshot.

The reason this troubles me is that we don't have a clear plan for how to manage COVID-19 when restrictions are relaxed. This will likely require testing. Lots of testing. Possibly individual people getting tested multiple times.

But we keep reading about "number of tests performed" and "number of negative tests" as if we can hit a magic number and then all is well. Testing helps diagnose individual patients. But on a population level, testing is a tool. We need a blueprint for the tool to be useful.

If we can develop & deploy antibody detection tests, this would be an even more useful tool on a population level. Antibody detection will tell you if someone was exposed to the SARS-CoV-2 virus in the past. With this test, you'd only need to test people once to get info you need

If you're curious about the differences between the two types of tests (virus nucleic acid vs antibody detection), this report from @mbiojournal is a good explainer. Here's their breakdown: https://mbio.asm.org/content/11/2/e00722-20

Follow-up thought: we don't yet know whether people can be re-infected with SARS-CoV-2. Data show that infected people produce antibodies which should provide protection against re-infection with the virus, but we're still learning about variation in people's immune responses

Essentially, negative result using nucleic acid COVID-19 test basically says "You're not infected now. We don't know anything about infection in the past or the future." We need a blueprint for managing COVID-19 to make this information useful on a population level.