You aren't legally allowed to know which variant gave you COVID-19 in the US, even if it's Delta

The Centers for Medicare and Medicaid Service (CMS), which oversees the regulatory process for US labs, requires genome-sequencing tests to be federally approved before their results can be disclosed to doctors or patients. These are the tests that pick up on variants, but right now, there's little incentive for the labs to do the work to validate those tests.

So far, Wroblewki said, more than 50 public labs in the US are capable of sequencing coronavirus samples to detect variants. But she's not aware of any labs that have completed the validation process to get federal approval.

"The process of validating a next-generation sequencing test is burdensome," Wroblewki said. "It takes a lot of time. It takes a lot of data. It takes a lot of resources. And the thing about the variants is that variants of concern and of interest are constantly changing, so you would have to do a whole validation every time you have a variant."