How worried should we be about XBB.1.5?
Katherine J. Wu writes: After months and months of SARS-CoV-2 subvariant soup, one ingredient has emerged in the United States with a flavor pungent enough to overwhelm the rest: XBB.1.5, an Omicron offshoot that now accounts for an estimated 75 percent of cases in the Northeast. A crafty dodger of antibodies that is able to grip extra tightly onto the surface of our cells, XBB.1.5 is now officially the country’s fastest-spreading coronavirus subvariant. In the last week of December alone,…