What to know about EG.5, the most prevalent COVID subvariant in the U.S.

The coronavirus has not disappeared. With the advent of successful vaccinations and better social management, however, it has waned.

Globally, over 1 million new COVID-19 cases and more than 3,100 deaths were reported in the 28 days up to Aug. 3, according to the latest World Health Organization report — bringing the death toll to almost 7 million since the pandemic began.

The attention of public health experts around the world is being piqued by a new subvariant, known as EG.5, which is becoming a dominant strain in countries including the United States and Britain.

Here's what we know.

What is the EG.5 coronavirus variant?

The EG.5 coronavirus is a subvariant and descendant of omicron — which remains the world's most prevalent coronavirus strain.

EG.5 has narrowly surpassed other omicron descendants circulating in the United States and now accounts for the largest proportion of COVID cases nationwide, according to the Centers for Disease Control and Prevention.

Twitter users and some media outlets have unofficially nicknamed the subvariant "Eris" in keeping with Greek nomenclature, but this name is not used officially by the WHO.

All viruses evolve and change over time. In its latest update, the WHO designated EG.5, which includes a similar EG.5.1 strain, as one of its "variants under monitoring," so it is not yet a variant of interest or concern.

The virologist and researcher Stuart Turville, an associate professor at Sydney's University of New South Wales, called the EG.5 variant "a little bit more slippery" and "competitive" than its counterparts, able to "navigate better the presence of antibodies" produced by vaccines.

It is, however, only incrementally different from other subvariants, having evolved slightly to "give it a better ability to engage and enter cells a little bit better," he said.

Prof. K. Srinath Reddy at the Public Health Foundation of India likened the subvariant to one of "several Barbies in the same film" — noting that it was essentially a variation of other omicron descendants.

EG.5 belongs to a family of subvariants "all within the overall umbrella of omicron," he said in an interview. As with other omicron variants, it is "less invasive and lethal in the body" and "this still remains the general observation," for EG.5, noted Reddy, a physician.

"It's clear we're going to be seeing this particular variant have its own day in the sun or period of dominance for some time before it's replaced by yet another variant," he said. "That's the nature of the virus."

EG.5, although more infectious, is not more virulent, and the response to it is generally the same as for other variants because "the impact on the human body is just about the same," he added.

What symptoms may be associated with EG.5?

The symptoms for this subvariant remain common to the coronavirus in general and can range from mild effects to more-serious illness.

They can include a cough, fever or chills, shortness of breath, fatigue, muscle or body aches, new loss of taste or smell, and headaches.

According to Reddy, EG.5 tends to cause symptoms such as a runny nose, sneezing and a dry cough. He added, however, that with seasonal fluctuations and a lack of testing, differentiating an EG.5 infection from a flu or the common cold can be difficult.

Vaccines and boosters still should be encouraged, as should safe social practices such as wearing face masks and keeping rooms well ventilated, health experts say.

The elderly may be most vulnerable to new strains, as their immunity from vaccination can wane more rapidly. But EG.5 should not be an immediate cause for concern, Reddy said.

"It is not increasing the number of cases in intensive care, or deaths," he said, although it may be responsible for more hospitalizations, especially among the elderly.

"But we have to keep up our vigilance," he added. "COVID-19 is still with us, but there's no need to panic with this particular variant."

Where is EG.5 being reported?

In the United States, the EG.5 variant — responsible for 17.3 percent of all coronavirus cases reported during the two-week period ending Aug. 5 — is the most prevalent in the country, according to the CDC tracker.

In the previous two-week period, ending July 22, EG.5 cases were nearly 12 percent of all reported cases, the CDC said. XBB.1.16, sometimes called "Arcturus," also remains prevalent in the United States, accounting for nearly 15.6 percent of recently reported cases.

Elsewhere, cases of the subvariant EG.5.1 have been reported in countries including Britain, India and Thailand. EG.5.1 was first flagged for monitoring in early July, the UK Health Security Agency said, after reports of its surfacing in Asia. Nearly 12 percent of all samples sequenced in late July were classified as EG.5.1, the agency said.

"The COVID-19 virus has not gone away and we expect to see it circulating more widely over the winter months with the numbers of people getting ill increasing," Mary Ramsay, the director of public health programs at the UK Health Security Agency said in a statement.

How dangerous might EG.5 be?

"There's currently no evidence to suggest that it causes more-severe illness," Andrea Garcia, the American Medical Association's vice president for science, medicine and public health, said in late July. "And the CDC is indicating that it does appear to be susceptible to coronavirus vaccines, which is good news," she added.

Like Reddy, Turville thinks the variant is not of "significant concern" despite the fact that it "transmits well," and he advises those who have not received booster shots or been vaccinated or infected with coronavirus in the past six months to consider getting immunized.

Will the new boosters work against EG.5?

In the United States, health officials are preparing this fall to administer booster doses of coronavirus vaccines made with a new formula targeting the XBB subvariants that have accounted for most infections in 2023.

The physician Eric Topol, a professor of molecular medicine at Scripps Research, said there is enough overlap between the different variants to believe that the new booster would protect people infected with EG.5 against severe disease. He said the updated boosters will be better aligned against the viruses circulating now than the current formula targeting the BA.5 subvariant that became dominant in summer 2022.

The rise of the new subvariant illustrates the challenges public health officials face trying to keep up with an ever-evolving virus, Topol said. "The 'pandemic is over' culture is the last thing we need to confront the pressure we've put on the virus to find new ways to get us — to find repeat and new hosts — and evade our prior immunity," Topol wrote in a Substack post Sunday.

Is COVID-19 still a big deal?

Many regions continue to report declines in illnesses and deaths linked to COVID, the WHO said in its latest update. However, countries including South Korea, Brazil, Australia and New Zealand were among those having the highest number of reported cases in the past month. A lack of testing and reporting to the WHO also makes figures hard to monitor, the agency said.

In general, the coronavirus "remains a major threat," the WHO said in an update, although the international public health emergency was declared May 5 to be officially over. "WHO continues to urge Member States to maintain, not dismantle, their established COVID-19 infrastructure. It is crucial to sustain surveillance and reporting, variant tracking, early clinical care provision," it added.

Although some people understandably want to put the pandemic behind them, Turville said, it's a "virus we live with now," like influenza, and does require regular monitoring.

"We are still working in the background, even if it's not front page news," he added.