New Covid variants Nimbus and Stratus are soaring – and there are unusual symptoms
Two newly identified COVID-19 variants — nicknamed Nimbus and Stratus — are driving a fresh wave of infections across the UK and the US, and doctors are warning that the symptoms may feel different from those seen in earlier strains.
A croaky, hoarse voice and an intense, “razor-blade” sore throat have emerged as two of the most recognizable signs of these latest variants, officially labeled NB.1.8.1 (Nimbus) and XFB (Stratus). Both are sublineages of Omicron, but experts say they are spreading faster and presenting slightly altered symptom profiles compared to previous versions of the virus.
A Sharp Rise in Cases
According to the UK Health Security Agency (UKHSA), national positivity rates jumped from 7.6% to 8.4% within a week — a significant uptick as autumn transitions into winter. Hospital admissions also rose from 2.0 to 2.73 per 100,000 people, marking the sharpest increase since early summer.
Across the Atlantic, U.S. health authorities are seeing similar trends. The Centers for Disease Control and Prevention (CDC) reports that COVID-19 wastewater levels — a key indicator of community spread — are now rated “moderate” nationwide. However, several states, particularly in the Northeast, are recording “very high” concentrations, suggesting another potential winter surge.
The Tell-Tale Symptoms
Doctors say patients infected with Nimbus or Stratus are reporting a distinct set of complaints.
Dr. Aaron Glatt, an infectious disease specialist based in New York, told Today.com:
“Patients describe the sore throat as feeling like their throat is lined with razor blades. It’s severe, and it’s often the first sign they notice.”
Other symptoms remain familiar — including headaches, congestion, fatigue, coughing, and muscle aches — but the throat pain and hoarseness appear to stand out with these new subvariants. Some patients also report losing their voice entirely for a few days, even when other symptoms remain mild.
Health experts emphasize that despite their increased transmissibility, Nimbus and Stratus are not believed to cause more severe illness than previous Omicron strains. However, they do seem to spread more efficiently, possibly because of subtle mutations that help them evade existing immunity from vaccines and prior infections.
Vaccination Campaign Intensifies
In response to the rising numbers, the UK has launched its winter vaccination drive earlier than usual. Millions are being urged to book their updated COVID and flu shots, particularly those in high-risk categories.
The current eligibility list includes:
- Adults over 75
- Residents and staff in care homes
- People with weakened immune systems
- Pregnant women
- Young children, who can receive the flu spray at participating pharmacies
Appointments can be made through the NHS app, online, or at designated walk-in clinics. Some private pharmacies are also offering paid COVID vaccinations for those not eligible under the NHS program, with prices ranging from £75 to £99 (approximately $95 to $134).
Dr. Mary Ramsay, head of immunization at the UKHSA, reminded the public that, “Vaccination remains the best protection against serious illness and hospitalization. Even if you’ve had COVID before, immunity can fade over time. Boosters keep that protection strong.”
What to Do If You’re Sick
UKHSA guidance remains consistent with previous “Living with COVID” recommendations: if you have a high temperature, feel unwell, or show respiratory symptoms, stay home if possible and avoid contact with vulnerable people.
If you must go out, wear a well-fitting mask to minimize the risk of transmission. COVID tests are no longer free through the NHS but are still available for purchase at local pharmacies and online retailers.
The agency’s statement reads:
“If you have symptoms of a respiratory infection and do not feel well enough to go to work or carry out normal activities, you should avoid contact with vulnerable people and remain at home where possible.”
The “Razor-Blade Throat” Explained
Doctors say the sharp throat pain associated with Nimbus and Stratus may stem from inflammation in the upper respiratory tract — particularly around the vocal cords. Unlike earlier strains that often caused lower respiratory infections and coughing fits, these variants seem to concentrate in the upper airway, causing intense soreness, hoarseness, and voice changes.
“It’s not unusual for viral evolution to shift symptom patterns,” said Dr. Glatt. “Viruses adapt, and our immune systems adapt in return. What we’re seeing now are milder systemic symptoms but more pronounced throat and sinus irritation.”
Are the Variants More Dangerous?
While both Nimbus and Stratus are more contagious, there is currently no evidence suggesting they cause more severe disease. The majority of cases remain mild to moderate, particularly among vaccinated individuals. However, the concern lies in the speed of spread — even a small percentage of severe cases can strain hospitals if total infections climb rapidly.
Experts stress that the best defense remains the same: vaccination, hygiene, and self-isolation when sick.
The Controversy: Vaccine and Cancer Claims
The recent surge in cases coincided with the release of a controversial South Korean study published in Biomarker Research, which claimed COVID vaccines “might raise the risk of cancer.” The study provided no mechanism or credible data to support that conclusion, and experts across the medical community have condemned it as “superficially alarming” and “scientifically unsound.”
“There is absolutely no credible evidence that COVID vaccines interfere with tumor suppression or promote cancer growth,” said Dr. Richard Sullivan, an oncologist at King’s College London. “This kind of speculation without evidence does real harm — it undermines public health efforts and feeds misinformation.”
Even the study’s authors acknowledged the limitations of their work but stopped short of retracting the claim. Health officials worldwide have reiterated that COVID vaccines remain safe, effective, and critical in preventing serious disease.
Broader Public Reaction
Public anxiety about new variants is understandably high, especially with memories of the pandemic’s earlier waves still fresh. However, most scientists agree the current situation, while concerning, is not comparable to 2020.
Population-level immunity — built through widespread vaccination and prior infections — has dramatically reduced the risk of severe illness. Hospitals are better prepared, treatments are more effective, and testing remains accessible.
Still, experts warn against complacency. The combination of waning immunity, colder weather, and increased indoor activity could lead to another winter spike.
“COVID isn’t gone — it’s just changed form,” said Dr. Glatt. “We have to treat it like we do the flu: it comes back, it evolves, and we have to adapt too.”
The Bottom Line
The emergence of Nimbus and Stratus marks yet another chapter in the evolving story of COVID-19 — a reminder that the virus continues to mutate and circulate, even as societies return to normal life.
The takeaway from health experts is clear:
- Stay up to date with boosters.
- Monitor symptoms, even unusual ones like hoarseness or sharp throat pain.
- Protect vulnerable people by staying home when sick.
- Rely on verified science, not viral rumors.
The world has come a long way since the early days of the pandemic, but the lessons remain the same: vigilance saves lives.
As Dr. Ramsay put it, “COVID may never disappear completely, but our ability to live safely alongside it depends on one thing — how seriously we take prevention.”
For now, Nimbus and Stratus are spreading fast. Whether they define another difficult winter depends not just on the virus, but on how we respond to it.