An emerging COVID-19 strain appears to cause conjunctivitis — also known as pink eye — especially in children, doctors say.

The XBB.1.16 subvariant — which has been nicknamed “arcturus” on social media — was first detected in January. It has been found in 42 countries, with India accounting for its biggest hotspot. 

In the United States, XBB.1.16, another descendant of the highly contagious omicron, accounts for about 12% of new cases, second behind XBB.1.5 at 69%, according to the Centers for Disease Control and Prevention.

Last week, the World Health Organization designated XBB.1.16 a variant of interest.

While the WHO noted that conjunctivitis has been a known, although rare, symptom with past COVID strains, some doctors, according to reports, say it appears to cause more fever and is more likely to produce pink eye.

According to the American Academy of Ophthalmology, conjunctivitis is an inflammation of the clear tissue covering the white part of of the eye and the inside of the eyelids. It results in eyes appearing red and swollen and producing a sticky discharge. Some types of pink eye can easily spread from person to person. 

Dr. Vipin Vashishtha, a pediatrician in India, tweeted earlier this month that he was seeing COVID-19 cases in children for the first time in six months and a trend was emerging of them having “itchy conjunctivitis w/ sticky eyes, not seen in earlier waves.”

The concerns about conjunctivitis come as allergy season is kicking into high gear in the U.S., and doctors caution not to assume pink eye is related to COVID-19. 

The American Academy of Ophthalmology notes that children frequently get conjunctivitis and that eye symptoms alone probably don’t point to COVID. If the child has been exposed to someone with the virus and appears to have pink eye, parents should contact their medical provider to discuss testing.

Previous studies have found adults with COVID-19 can also get conjunctivitis but at a much lower rate than children.

Arcturus can also have more common COVID symptoms, including fever, sore throat, running nose, body ache and fatigue.

While the WHO says XBB.1.16 has “immune escape properties” that could lead to it becoming the dominant strain in some countries, it does not appear to cause illness more severe than seen in XBB.1.5. The agency, however, noted there has been slight increases in hospital bed occupancy in India and Indonesia.

“It is very hard to predict,” Dr. Mike Ryan, the executive director of the WHO's emergencies program, said during a news conference last week. “We're not dealing with the same thing all the time. The virus continues to evolve, it continues to test our immune systems, it continues to try and evade those immune systems, so we have to remain vigilant.”

WHO Director-General Dr. Tedros Adhanom Ghebreyesus said Wednesday that the rise of XBB.1.16 illustrates that COVID-19 is still changing and capable of causing new surges in cases and deaths.

“We remain hopeful that sometime this year we will be able to declare an end to COVID-19 as a public health emergency of international concern but this virus is here to stay and all countries will need to learn to manage it alongside other infectious diseases,” he said.

According to the CDC, the  United States is averaging nearly 13,000 new infections a day, although that is believed to be a vast undercount due to less testing and unreported positive home tests. There were 1,052 COVID deaths in the U.S. last week.