Lee Harrison – The Conversation

A positive COVID-19 test is the first step in the process. Paul Hennessy/SOPA Images/LightRocket via Getty Images

January 7, 2022

From delta to omicron, here’s how scientists know which coronavirus variants are circulating in the US

Alexander Sundermann, University of Pittsburgh and Lee Harrison, University of Pittsburgh

A nationwide genomic surveillance system analyzes positive COVID-19 tests to build a picture of which variants are spreading in the population.

The huge number of active coronavirus infections offers plenty of opportunity for mutations to occur and new variants to arise. Eoneren/E+ via Getty Images

September 9, 2021

Massive numbers of new COVID–19 infections, not vaccines, are the main driver of new coronavirus variants

Vaughn Cooper, University of Pittsburgh and Lee Harrison, University of Pittsburgh

When the coronavirus copies itself, there is a chance its RNA will mutate. But new variants must jump from one host to another, and the more infections there are, the better chance this will happen.

Sequencing the genetic code of virus samples taken from COVID-19 patients reveals how SARS-CoV-2 is spreading and changing. Nate Langer/UPMC

March 31, 2021

Genomic surveillance: What it is and why we need more of it to track coronavirus variants and help end the COVID‑19 pandemic

Alexander Sundermann, University of Pittsburgh; Lee Harrison, University of Pittsburgh, and Vaughn Cooper, University of Pittsburgh

The US lags in testing coronavirus samples from COVID-19 patients, which can help track the spread of the virus and the emergence of new variants. But labs are ramping up this crucial surveillance.

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