The new COVID-19 strain known as "Arcturus" has increased in the U.S. so much that it has been added to the CDC's watch list.
Officially labeled XBB.1.16, Arcturus as a subvariant of Omicron that was first seen in India and has been on the World Health Organization's watchlist since the end of March. The CDC's most recent update now lists Arcturus as causing 7 percent of U.S. coronavirus cases, landing it in second place behind its long-predominant Omicron cousin XBB.1.5, which causes 78 percent of cases.
Arcturus is more transmissible but not more dangerous than recent chart-topping strains, experts say.
"It is causing increasing case counts in certain parts of the world, including India. We're not seeing high rates of XBB.1.16 yet in the United States, but it may become more prominent in coming weeks," Mayo Clinic viral disease expert Matthew Binnicker told The Seattle Times.
Arcturus has been causing a new symptom in children, Indian medical providers have reported.
"One new feature of cases caused by this variant is that it seems to be causing conjunctivitis, or red and itchy eyes, in young patients," Binnicker said. "This is not something that we've seen with prior strains of the virus."
More than 11,000 people in the U.S. remained hospitalized with COVID at the end of last week, and 1,327 people died of the virus last week, CDC data show. To date, 6.9 million people worldwide have died from COVID, the WHO says. Of those deaths, more than 1.1 million occurred in the U.S.