Rumsfeld's Unknown Unknowns

Some patients who recover from COVID-19 develop very few antibodies, a new early-stage study suggests, raising questions over the development of a vaccine and whether people get lasting immunity.  And perhaps the efficacy of viral antibody test results?

So, how big is that denominator number? Unfortunately, we don’t know. Worse, in the U.S., it is at this point, and for the very foreseeable future, unknowable. A second-order outrage about the pathetic, outrageous lack of test kits, and the backlog processing even the tests we do have, is that in addition to limiting our ability to treat those patients we know are ill and to take public-health measures to protect the vulnerable parts of our population, we have very little sense of the scale of the outbreak we are dealing with. When we can’t even test all those patients who show up at hospitals complaining of symptoms, we are miles from a clear sense of how many other people might be carrying the disease around — infecting others, of course, but also changing the size of that denominator.