New COVID variant XBB.1.16 under WHO observation as cases spike

The WHO called the new COVID variant "one to watch" and is monitoring the new variant, which has been dubbed Arcturus as it continues to spread.

 SARS-CoV-2, the novel coronavirus behind COVID-19 (Illustrative). (photo credit: fusion medical animation/unsplash)
SARS-CoV-2, the novel coronavirus behind COVID-19 (Illustrative).
(photo credit: fusion medical animation/unsplash)

A new COVID-19 variant called XBB.1.16 (or, unofficially, Arcturus) seems to be spreading faster than other recent variants but doesn't seem to cause more severe illness, according to initial studies.

The variant has garnered attention from both the media and the World Health Organization (WHO) after seemingly sparking a spike in cases in India in recent weeks. As of Wednesday, there were 40,215 active coronavirus cases in India, with 7,830 new cases recorded between Tuesday and Wednesday.

A pre-print study published by Japanese and Czech researchers found that XBB.1.16 is "robustly resistant to a variety of anti-SARS-CoV-2 antibodies" and appears to have a greater growth advantage compared to other Omicron variants like XBB.1 and XBB.1.5.

The researchers wrote that the variant's increased infectivity suggests that it will spread worldwide in the near future.

 Novel Coronavirus SARS-CoV-2 (credit: Wikimedia Commons) Novel Coronavirus SARS-CoV-2 (credit: Wikimedia Commons)

The Times of India reported earlier this week that different symptoms have been reported among pediatric cases of the coronavirus recently in India, including itchy conjunctivitis and sticky eyes, which were not present in preceding waves of the virus.

During a press conference in March, the WHO's technical lead on COVID-19, Dr. Maria Van Kerkhove, stated that the WHO is monitoring XBB.1.16, adding that it has one additional mutation in the spike protein compared to XBB.1.5 which in lab studies has been shown to increase infectivity.

Van Kerkhove also noted that XBB.1.16 has replaced the other variants that are in circulation in India. "This is one to watch. It has been in circulation for a few months."

"This is one to watch. It has been in circulation for a few months."

Dr. Maria Van Kerkhove, WHO technical lead on COVID-19

Over 600 sublineages of Omicron in circulation

According to Van Kerkhove, there are over 600 sublineages of Omicron in circulation.

Other Omicron subvariants have sparked alarm in the past.

In January, health officials expressed concerns about the XBB.1.5 variant, with the WHO calling it "the most transmissible variant that has been detected yet."

In October of last year, researchers expressed concerns about the BA.2.75.2, BF.7 (also known as BA.5.2.1.7) and BQ.1.1. variants as they seemed to have evolved to evade immunity better.