Health officials have started monitoring BA.2.86 — a highly mutated version of the COVID-19 virus. Not much is known yet about the newly detected lineage, though its large number of mutations has prompted the World Health Organization and CDC to begin tracking the strain.
The World Health Organization added BA.2.86, dubbed "Pirola" on social media by scientists closely tracking evolutionary changes in the virus, to its list of variants under monitoring Aug. 17. Shortly after, the CDC also said it has started tracking the lineage.
"CDC is gathering more information and will share more about this lineage as we learn it," the agency said on the social media platform X, formerly known as Twitter. So far, BA.2.86 has been detected in Israel, Denmark, the U.S. and the U.K. So far, only six cases of the new strain have been identified, with the single U.S. case detected in Michigan.
As of right now, the main concerns are around the sheer number of changes the lineage has, which experts say is on par with the evolutionary jump that led to omicron's emergence.
"This variant has lots of amino-acid mutations in spike: 33 relative to its putative BA.2," the Bloom Lab said in an Aug. 16 tweet, adding that it's also very different than XBB.1.5, which COVID-19 shots slated to arrive this fall were updated to target. "This makes it an evolutionary jump comparable in size to that which originally gave rise to micron," the tweet said. Bloom Lab is run by Jesse Bloom, PhD, an evolutionary biologist at Seattle-based Fred Hutchinson Cancer Center.
For now, EG.5 remains the dominant strain in the U.S., according to the latest variant proportion updates from the CDC. BA.2.86 will continue to be grouped in with its distant parent BA.2 until it accounts for at least 1 percent of cases.