The World Health Organization (WHO) has identified a recent “stealth omicron” strain, feared to be more transmissible and evasive than the previous variants.

Officially named BA.2.75 and nicknamed “Centaurus,” the brand new subvariant has been present in 10 countries, including Australia, Canada, Japan, Recent Zealand, Germany, the US and the UK.

The subvariant has recently risen to prominence in India, where it’s competing with omicron. However the WHO has not named it a variant of concern yet.

In an update released via Twitter, WHO officials said initial data on the subvariant is currently limited. Its overall transmissibility, severity, and potential for immune evasion are currently unknown.

Dr. Eric Topol, a professor of molecular medicine at Scripps Research and founder and director of the Scripps Research Translational Institute, identified on Twitter that the subvariant has “eight mutations beyond BA.5, many within the N-terminal domain, which could make immune escape worse than what we’re seeing now.”

Topol also quoted Dr. Ulrich Elling, a molecular biologist, who said the U.S. might “have to organize” for the Centaurus wave because he didn’t “just like the observed mutations.”

“The variety of eight additional mutations in BA.2.75 is remarkable. Delta had eight in spike in total. Three mutations could make an enormous difference (BA.5). Thus the 11 mutations distinct between BA.5 and BA.2.75 could allow for yet one more wave as BA.5 immunity won’t protect,” tweeted Elling.

WHO chief scientist Dr. Soumya Swaminathan said more research is required to raised understand its transmissibility and severity. In response to her, it’s still too early to know if Centaurus has properties of additional immune invasion.

“We don’t know that, so now we have to attend and see,” she noted. 

The omicron subvariant is currently dominant within the U.S., estimated to have caused nearly 54% of infections within the U.S. last week, in keeping with data released by the U.S. Centers for Disease Control and Prevention.

In a post made last week, Dr. Topol called omicron the “worst version of the virus that we’ve ever seen” as a result of its enhanced transmissibility.