Summer may bring beach trips and backyard barbecues, but it also tends to bring a rise in Covid cases.
In its latest report, the CDC said infections — particularly those linked to the Nimbus and Stratus variants — are increasing or likely increasing in at least 26 states and Washington, D.C. Emergency room visits for young children have also reached their highest level since March.
While these seasonal bumps aren’t unusual, medical experts say they shouldn’t be ignored.
“We now know that there’s a winter spike and then there’s a summer spike,” Jon LaPook, MD, told CBS Mornings on Monday. “And every year, I just looked last night, the number of deaths, the number of hospitalizations, is gradually going down each season. So that’s the good news.”
What is the NB.1.8.1 or Nimbus variant?
A new Covid variant is making headlines for a symptom that sounds like it’s straight out of a horror movie: a searing sore throat that feels like it’s lined with razor blades. NB.1.8.1, or “Nimbus,” was first identified in January 2025 and has been steadily spreading since. It evolved from XDV.1.5.1 and is now on the World Health Organization’s radar as a “variant under monitoring” due to its growing global presence.
The earliest surge tied to NB.1.8.1 was reported in China, but it didn’t take long to spread. By late March and early April, U.S. health officials detected it in travelers arriving at California, Washington, Virginia, and New York airports. Additional cases have since been reported in other states, signaling a broader reach.
This particular strain causes “razor blade throat,” or a severe sore throat. Other symptoms reportedly include: Congestion, fatigue, fever, and muscle aches.
What about the Stratus variant?
Like NB.1.8.1, Stratus is a subvariant of Omicron. The World Health Organization officially designated it a “variant under monitoring” in late June.
First detected in Canada in January, Stratus has since spread to at least 38 countries — including much of Europe, the U.S., and large parts of Southeast Asia. It now makes up an estimated 22 to 23 percent of global Covid cases.
One symptom that stands out with Stratus infections is hoarseness. Patients have also reported dry coughs and sore throats, along with more familiar Covid symptoms like fever, muscle aches, and fatigue.
Where Covid cases are growing
Covid cases are growing in these states, according to the CDC:
- Arkansas
- Hawaii
- Illinois
- Iowa
- Kentucky
- North Carolina
- Ohio
- Pennsylvania
- Texas
- Virginia
Where Covid cases are “likely growing”
The CDC says Covid cases are likely growing in the following places:
- Alaska
- California
- Delaware
- District Of Columbia
- Georgia
- Indiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Mississippi
- New Jersey
- New York
- Oklahoma
- South Carolina
- Tennessee
- Wisconsin
Are the latest Covid variants more contagious?
Both NB.1.8.1 and Stratus appear to spread more easily than earlier variants, with Stratus showing a stronger ability to transmit in both lab studies and real-world settings.
“I know that everybody wants to forget about this disease, but it’s not going to allow us to,” Janko Nikolich, MD, Ph.D., professor and chair of the Department of Immunobiology at the University of Arizona College of Medicine, told ABC Action News in June.
Still, neither variant has been linked to more severe illness. According to the World Health Organization, current data does not indicate that they cause more serious disease than previous strains.
The uptick in cases may also be seasonal. Covid infections often rise in the summer — and this year appears to be following that trend, particularly in countries like China.
Do the current Covid vaccines protect against these variants?
The WHO says current Covid vaccines should still offer protection against both the NB.1.8.1 and Stratus variants. But there’s a catch: getting a booster might not be as easy as before.
The FDA has limited updated boosters to people 65 and older and those with certain health conditions. In May, Health and Human Services Secretary Robert F. Kennedy Jr. also announced that routine Covid vaccine recommendations would be dropped for healthy children and pregnant women, even though pregnancy remains a high-risk factor for severe complications.
Still, the CDC hasn’t ruled out vaccination for these groups entirely. Instead, it now encourages “shared clinical decision-making” — meaning shots are still available if individuals (or parents) choose to get them in consultation with a healthcare provider.
Beyond vaccination, basic precautions still matter: Wash your hands regularly, cover your coughs and sneezes, and consider bringing back your N95s in crowded indoor spaces. A few simple steps can go a long way in keeping yourself — and your community — safer.
