What You Need to Know About the XBB.1.16 'Arcturus' Variant

Another COVID variant is gaining ground. The World Health Organization (WHO) has designated XBB.1.16 as a variant of interest (VOI). At first, XBB.1.16 was classified as a variant under monitoring (VUM), but the WHO decided the variant’s quick spread around the world required more action.

Since it was first reported in January, the variant has now been detected in 33 countries. Within four weeks of tracking by epidemiologists (February 27 to April 2) the global prevalence of the variant increased by more than 3%.

Here’s what experts want you to know about the Arcturus COVID variant.

Where Did XBB1.16 Come From and Where Is It Now?

Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health, told Verywell that it’s not clear where the variant originated, but it appears to be most prominent in India.

After India, most cases are have been reported in the United States, Singapore, and Australia, according to the WHO.

“The first case in the U.S. probably went unnoticed as most COVID cases are not sequenced,” said Adalja.

Data from the Centers for Disease Control and Prevention (CDC) shows that cases of XBB.1.16 were already sequenced in March and have been gradually rising since. The variant accounted for almost 10% of sequenced cases in the U.S. last week, up from almost 6% the week before. 

Since XBB.1.16 is starting to displace the other versions of Omicron, Adalja said that the variant’s mutations are likely advantageous. That means it could become the dominant version of COVID, just as other variants that came before did.

What Are the Symptoms of XBB.1.16?

The most common symptoms of COVID are still more or less the same as they’ve been throughout the pandemic: a sore throat, new loss of taste or smell, trouble breathing, and congestion.

However, Vincent Hsu, MD, an infectious disease specialist and infection control officer for AdventHealth, told Verywell that reports from India have shown that the XBB.1.16 variant appears to be associated with conjunctivitis (also called “pink eye”) as well—especially in kids.

“Many viruses and some bacteria can cause similar symptoms along with the usual respiratory symptoms,” said Hsu. “So, it is important to test for COVID-19 if suspected.”

More than one respiratory virus is going around, though—for example, the flu and respiratory syncytial virus (RSV). That’s why Hsu said it’s important to get tested—the treatment depends on which virus you have.

Will We Need a New COVID Vaccine for XBB.1.16?

A preprint study posted online in early April suggested that the ability of XBB.1.16 to get around the immune system is similar to what XBB.1 and XBB.1.5. could do.

Hsu said that every new variant has additional mutations that are likely to make current vaccines less effective. However, it’s too early to tell if XBB.1.16 on its own will mean we need to make an updated vaccine.

According to Hsu, new strains have “a fitness advantage” like being able to resist vaccines which gives them a chance to “circulate with increasing transmission.” However, at the moment, Hsu said that there is no confirmation that XBB1.16 is “causing any more severe disease.”

Right now, data is not showing that XBB.1.16 is more dangerous than the other Omicron variants going around. However, it’s still important to take steps to avoid the virus, which includes staying up-to-date on vaccines and boosters.

Last week, the Food and Drug Administration (FDA) authorized an additional dose of a bivalent COVID vaccine for older adults and immunocompromised people. People who have already received a single dose of the bivalent vaccine are not currently eligible for another one. 

“Vaccines will continue to do what their primary aim is: prevent severe disease,” said Adalja. “It’s unlikely that this variant would prompt a change in [the] formulation of the vaccine.”

XBB.1.16 isn’t the first new variant we’ve had to deal with—and it’s not going to be the last. As Adalja explained, “there will always be a new variant that arises—that’s how evolution works.”