Coronavirus Variants Have Nowhere to Hide

Any diagnostic test worth its salt has precision on its side. It can pinpoint the presence of this condition, but not that one; it can, when used for an infectious disease, distinguish between microbes that look very much the same.

For most of the pandemic, that exactness has been a major asset for the hundreds of tests that detect SARS-CoV-2. But the discerning nature of most tests has also opened up a weak point for the coronavirus to exploit. With the virus mutating into new and concerning variants, a few of the tests designed to recognize its original iteration are now getting duped. What was once a singular target has split itself off into many, many bull’s-eyes, each a little different from the next, and we’re having trouble taking aim.

This isn’t yet a crisis, and perhaps it never will be. Mosttests are still performing very well against all known versions of the coronavirus, and researchers have work-arounds that will buttress others against the virus’s shape-shifting. But keeping tabs on test performance is crucial, especially while the pandemic rages on in many parts, which means that test manufacturers will need to closely track the virus’s movements and tailor their products to follow it. More than a year out from the time when experts first got eyes on the virus, tests are in need of a touch-up.