From delta to omicron, here's how scientists know which coronavirus variants are circulating in the US
- Written by Alexander Sundermann, Clinical Research Coordinator & DrPH Candidate in Epidemiology, University of Pittsburgh Health Sciences

The omicron variant quickly took over the global coronavirus landscape after it was first reported in South Africa in late November, 2021. The U.S. became the 24th country to report a case of omicron infection when health officials...