After a slow start, the United States has improved its surveillance system for tracking new coronavirus variants such as omicron, boosting its capacity by tens of thousands of samples per week since early this year.
Viruses mutate constantly. To find and track new versions of the coronavirus, scientists analyze the genetic makeup of a portion of samples that test positive.
They’re looking at the chemical letters of the virus’s genetic code to find new worrisome mutants, such as omicron, and to follow the spread of known variants, such as delta.
It’s a global effort, but until recently the U.S. was contributing very little. With uncoordinated and scattershot testing, the U.S. was sequencing fewer than 1% of positive specimens earlier this year. Now, it is running those tests on 5% to 10% of samples.