Just as emergency orders are being lifted and testing sites close, a new omicron subvariant of COVID-19 has the World Health Organization’s attention as it spreads in India and the United States, including Massachusetts.
XBB. 1.16, also called Arcturus, was first detected by the WHO on Jan. 23 before designating it as a new “variant under monitoring” on March 22.
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This designation is less serious than a variant of interest or variant of concern, but the WHO said there are “early signals” that Arcturus is dominating over other subvariants, including XBB 1.15, or the “Kraken” subvariant.
Arcturus has been found in 29 countries as of April 13, according to the WHO. India is experiencing a surge in cases, with over 60,000 COVID cases reported, its health ministry reported on Monday. Arcturus is replacing other variants in circulation on the subcontinent, according to WHO epidemiologist Maria Van Kerkhove during a press conference in March.
During that same press conference, Van Kerkhove said Arcturus is currently the most transmissible variant yet. New mutations in the virus’ spike protein now create the added potential to infect more easily, making Arcturus “one to watch,” Van Kerkhove added.
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In the United States, cases of Arcturus have slowly ticked upward, accounting for 7.2% of COVID-19 infections in the U.S. during the week of April 9–15, according to the Centers for Disease Control and Prevention. Arcturus has been reported in 23 states, according to the CDC’s COVID tracker.
In Massachusetts, Arcturus counts for less than 1% of cases thus far, according to the CDC. The state with the highest percentage of cases is Delaware, where almost 3% of COVID infections are Arcturus.
Arcturus is also distinct because of a new symptom not commonly seen with past COVID infections. Red, itchy eyes resembling conjunctivitis, or pink eye, has been seen among Indian children sick with the Arcturus subvariant, assistant dean of research and associate professor at the New York Institute of Technology Raj Rajnarayanan told Fortune.
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Despite its rise, reported cases of Arcturus remain low in the United States. No hospitalizations or deaths as a result of Arcturus have been reported, but director of the Clinical Virology Laboratory at the Mayo Clinic Dr. Matthew Binnicker told NBC 5 Chicago that the strain “may become more prominent in coming weeks.”
