XBC—a combination of Delta and “stealth Omicron” BA.2 circulating in Asian countries like the Philippines—has the greatest potential in the group for transmission, variant tracker Raj Rajnarayanan, assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Ark., tells Fortune.Because XBC contains the viral body of Delta and the spike protein of Omicron, it’s less likely to combine the easy transmissibility of Omicron with the deadly penchant of Delta to hide out in the lungs, experts say.Other Deltacrons reported earlier this year, including XD in France and XS in the U.S., never took off, perhaps because they were less transmissible than “stealth Omicron.”Regardless of how these Deltacrons play out this fall, there’s always potential for another.While the bulk of Delta infections in animals have been detected in North America, they’ve also been reported in Lithuania, Switzerland, Hong Kong, Poland, Latvia, the Netherlands, Canada, South Africa, and additional countries.Such a variant—transmitted by the animals or immunocompromised patients it developed in—has the potential to be the next “big thing” in coronavirus evolution, the likes of which haven’t been seen since Omicron burst onto the scene roughly a year ago."