Coronavirus: Future variants-of-concern likely lurk in today's patients

The many coronavirus particles inside an infected person likely include some mutated ones that may turn out to be early examples of important variants, new findings suggest.

Closely analyzing virus particles obtained from 10 people with infections attributed to the Alpha variant in Spain in April 2021, researchers identified some mutated particles resembling the Omicron variant, which was not formally identified until seven months later.

They also found mutations characteristic of a form of Delta and Iota, according to a report published on Tuesday in the Journal of Clinical Investigation. While identifying an individual patient’s dominant variant may be sufficient for diagnostic purposes, the “ultra deep” genetic sequencing used in this study could help scientists track mutations in SARS-CoV-2 particles that might evolve into variants of concern, the researchers said.

“The virus that replicates in each infected patient is in reality a mixture of slightly different SARS-CoV-2 viruses,” and these different viruses account for varying proportions of the full “ensemble,” said coauthor Celia Perales of Universidad Autonoma de Madrid. Minority variants in one infected individual can become dominant in someone else, either by chance, or due to a selective advantage related to the presence or absence of drugs, vaccines, or other factors, she said.