...
By Alice Gibbs
Senior Reporter
0
Share
Newsweek is a Trust Project member
See more of our trusted coverage when you search.Prefer Newsweek on Googleto see more of our trusted coverage when you search.
New cases of COVID-19 are increasing nationwide, fueled by the Stratus variant, an emerging offshoot of the Omicron variant.
According to the Centers for Disease Control and Prevention (CDC), the national test positivity rate hit 9.9 percent in the past week, up 1.4 percent from last week.
CDC data show the sharpest increases are in the U.S. South, where test positivity rates in some states have hit 15 percent.
Read More on Health
"Currently, the most prevalent lineage in the U.S. is XFG, based on CDC's recent surveillance estimates," a CDC spokesperson told Newsweek:
This variant is the most common in both clinical specimens and wastewater data."
What is the Stratus variant?
The COVID-19 Stratus variant—also known as "XFG"—is a subvariant of Omicron.
Researchers believe that it emerged through recombination of earlier Omicron lineages, giving it mutations that may make it spread faster and evade immunity.
The World Health Organization (WHO) currently lists Stratus as a "variant under monitoring," meaning it is circulating widely but has not been shown to cause more severe illness.
Although the strain is being monitored, "variant under monitoring" is the lowest of the WHO's alert tiers, which also include variants of interest and variants of concern.
Current data does not indicate that this variant leads to more severe illness or deaths than its counterparts.
By late June, Stratus accounted for 14 percent of all U.S. cases. It is now among the three most common COVID-19 strains in the U.S., alongside Nimbus and LP.8.1.
Stratus is not just spreading in the U.S. either. The World Health Organization reports that as of late June 2025, XFG accounted for approximately 22.7 percent of global COVID‑19 sequences, up from 7.4 percent in early May, and was detected in 38 countries.
Scott Roberts, assistant professor of infectious diseases at Yale School of Medicine, told Newsweek: "This is still an Omicron subvariant. We're all still in the same family tree here. I've seen no data to suggest that this is more severe and it leads to worse outcomes in patients than any prior variant."
He added that its rapid growth likely reflects "the natural evolution of viral infection," with immunity from past infections and vaccinations waning.
COVID-19 Stratus variant symptoms
According to the CDC, the symptoms of COVID-19 to look out for include:
- Congestion, cough, fatigue, headache and mild fever;
- New loss of taste or smell;
- Muscle, head and body aches;
- Cough and sore throat.
Some reports have linked Stratus to a particularly severe sore throat, sometimes called "razor blade throat."
Roberts, however, cautioned against overstating this and said: "I've not seen any data to suggest there's different symptoms with this Stratus variant compared to prior.
"There's certainly anecdotes out there and I think the one, the razor blade throat, is kind of the concerning one I've heard for Nimbus variant."
He added: "It's unclear to me why this variant would lead to a more severe sore throat than other variants. My best guess is this is an anecdote that kind of spread because it's a catchy name."
"There is no data to indicate that XFG causes more severe COVID-19," the CDC said.
"CDC is not aware of any new symptoms associated with XFG or any other co-circulating SARS-CoV-2 lineage. CDC will continue to track all SARS-CoV-2 variants.
Southern states driving the surge
The latest CDC maps show that the south has become the epicenter of the current surge, with Arkansas, Louisiana, Oklahoma and Texas reporting positivity rates higher than anywhere else in the country.
COVID-19 vaccinations
The CDC currently recommends a 2024–2025 COVID-19 vaccine for most adults ages 18 and older.
Earlier this month the American Academy of Pediatrics (AAP) issued independent COVID-19 vaccine guidance that diverges from the Centers for Disease Control and Prevention for the first time in three decades.
The AAP's recommendations call for routine vaccination of children ages 6 months to 2 years, citing elevated risks of severe illness in that age group. The guidance also supports vaccination for older children with underlying health conditions or at parental discretion.
This is contrary to the latest CDC guidance which, under the leadership of Secretary Robert F. Kennedy Jr., no longer recommends COVID-19 vaccines for healthy children or pregnant women.
Roberts stressed that vaccination remains critical, particularly for vulnerable groups, saying: "Vaccine is always gonna be the best tool."
He also encouraged those at high risk for COVID-19 to consult their doctor and prepare ahead of the winter virus season, when COVID-19, flu and RSV are all expected to rise.
Do you have a tip on a health story that Newsweek should be covering? Do you have a question about COVID? Let us know via health@newsweek.com.
Update 08/28/25 05:10 a.m.: This article was updated with new comments from the CDC.
View 0 Comments
Submit Correction
View Editorial & AI Guidelines