The B117 variant of the virus responsible for COVID-19 has been spreading for longer than previously known, researchers have found.

The highly contagious SARS-CoV-2 variant was unknowingly spreading for months in the United States by October 2020, according to the new study.

Scientists first discovered it in early December in the United Kingdom, where the highly contagious and more lethal variant is thought to have originated.

The study provides evidence that the coronavirus variant B117 (501Y) had spread across the globe undetected for months when scientists discovered it.

“By the time we learned about the UK variant in December, it was already silently spreading across the globe,” says Lauren Ancel Meyers, the director of the COVID-19 Modeling Consortium at the University of Texas at Austin and a professor of integrative biology. “We estimate that the B117 variant probably arrived in the US by October of 2020, two months before we knew it existed.”

Analyzing data from 15 countries, researchers estimated the chance that travelers from the UK introduced the variant into 15 countries between September 22 and December 7, 2020. They found that the virus variant had almost certainly arrived in all 15 countries by mid-November. In the US, the variant probably had arrived by mid-October.

“This study highlights the importance of laboratory surveillance,” Meyers says. “Rapid and extensive sequencing of virus samples is critical for early detection and tracking of new variants of concern.”

In conjunction with the paper’s publication, consortium members developed a new tool that decision-makers anywhere in the United States can use in planning for genetic sequencing that helps to detect the presence of variants. To help the US expand national surveillance of variants, the new online calculator indicates the number of virus samples that must be sequenced in order to detect new variants when they first emerge.

Read the full article about COVID-19 variants at Futurity.