Nimbus Variant Razor Throat COVID: Symptoms, What Happened, and Where It Stands in October 2026

Medically reviewed by Dr. Adam N. Khan, MD · Last updated October 7, 2026 · 14-minute read

A quick note before you read: This is general health information, not personal medical advice, and it cannot diagnose you. If you have trouble breathing, can’t swallow liquids, are drooling, or your throat pain is far worse than anything you’ve had before, contact a clinician or urgent care now rather than finishing this article.

Quick answer: The Nimbus variant, officially NB.1.8.1, is an Omicron descendant that drove a global COVID wave in mid-2025 and became famous for a brutally painful sore throat nicknamed “razor throat,” a sharp, stabbing pain when swallowing. The World Health Organization has labeled it a Variant Under Monitoring since May 23, 2025 and rated its additional public health risk as low, and vaccines were expected to remain effective against it. Its US peak came in late June 2025 at about 43% of cases; by late August 2026 it had fallen to roughly 3%, overtaken by the Stratus family. [2][14] If you have razor-blade throat pain today, COVID and strep are still the first things to rule out with tests, and the pain responds to ordinary anti-inflammatory treatment.

Type “razor throat” into a search bar and you will meet a wall of articles from June 2025, written when Nimbus was climbing toward dominance in the United States and the phrase “razor blade throat” was everywhere. Most of those pages have not been touched since. Some now recommend vaccine guidance that is two seasons out of date, and a few recycled articles even repeat the 2025 case-share numbers under 2026 datelines. So this guide does two jobs at once: it explains the razor throat completely, what it feels like, why it hurts, how to treat it, and when to worry. And it tells you what actually happened to the Nimbus variant, because the answer is more interesting than the headlines suggested, and no page currently ranking for this keyword includes it.

What Is the Nimbus Variant (NB.1.8.1)?

Nimbus is the unofficial nickname for NB.1.8.1, a SARS-CoV-2 variant that descends from the recombinant lineage XDV.1.5.1 within the broad JN.1 (Omicron) family. The earliest known sample was collected on January 22, 2025. The “Nimbus” name was coined in late May 2025 on X by T. Ryan Gregory, a Canadian evolutionary biologist who also created several earlier variant nicknames; “Nimbus” and “Stratus” are cloud-themed labels from the same informal series, and they are not official WHO names.

The WHO designated NB.1.8.1 a Variant Under Monitoring on May 23, 2025, one rung on the ladder below a Variant of Interest. Its risk evaluation noted that the variant carries spike changes, including a substitution at position 445 that strengthens binding to the human ACE2 receptor and changes at positions 435 and 478 that modestly reduce the potency of some antibodies, which helps explain its transmissibility. At the same time, the evaluation found only a 1.5 to 1.6 fold reduction in neutralization by vaccinated blood plasma compared with the then-dominant LP.8.1.1, and concluded the additional public health risk at the global level was low, with approved vaccines expected to remain effective against symptomatic and severe disease.

Translation: Nimbus caught on because it glides into cells a little better than its rivals, not because it defeats immunity or makes people dramatically sicker. Lab work found it infected cells up to 2.5 times more efficiently than the previous leading variant, which is about entry, not severity. Early US surveillance showed case and hospitalization rates staying stable even as the variant spread. [9] “Early and limited laboratory data do not show a significant capability to evade the immune system or increased resistance to antiviral treatment,” Dr. Kartik Cherabuddi of Tampa General Hospital told Healthline at the time.

The Full Nimbus Timeline: From Emergence to 3%

No ranking article tells this story, which is strange, because the story is the most useful thing a 2026 reader can learn from it: variants rise, get famous, and get replaced, usually within months.

Date	What happened	Source
Jan 22, 2025	Earliest NB.1.8.1 sample collected	WHO [1]
Apr 2025	Global share of sequenced cases rises from 2.5% to 10.7% in four weeks; 518 sequences from 22 countries	WHO [1]
Mar 2025	First US detections, through international airport screening	TODAY [2]
May 23, 2025	WHO designates NB.1.8.1 a Variant Under Monitoring; risk rated low	WHO [1]
Late Jun 2025	US peak: an estimated 43% of cases in the two weeks ending June 21; dominant by July; detected in 31 states and DC	TODAY/CDC [2]
Jul-Sep 2025	Stratus (XFG) overtakes Nimbus in the US during the summer; in the UK, Nimbus slips to about 7% by early July; global share about 11% by late September	KQED/Mirror [10][11][12]
Aug 2025	Bay Area snapshot: Stratus at 82% of wastewater detections, Nimbus at 5.2%	KQED/Stanford [10]
Early Jan 2026	US: Stratus and descendants at 60 to 70% of cases; Nimbus down to about 5%	Aurametrix [13]
Jan 2026	Germany: Nimbus briefly the most frequent lineage (52% of a small 48-sequence sample)	RKI via Parahealth [14]
Jul 27, 2026	WHO’s monitoring list still includes NB.1.8.1; its descendant PQ.16.1.1 (earliest sequence Mar 25, 2026, mostly Singapore) is added as a new Variant Under Monitoring	WHO via Parahealth [14]
Aug 29, 2026	CDC 4-week estimates: SW.2 leads at 33%, NB.1.8.1 at about 3% of US cases	CDC via Parahealth [14]

Two honest caveats belong next to that table. First, variant tracking runs on far fewer sequenced samples than it used to; the CDC itself flags its precision as “low,” and the WHO’s global dashboard for late July to late August 2026 rested on just 216 sequences worldwide, of which NB.1.8.1 made up about a fifth. Second, that means any single percentage is a rough sketch, not a census. The direction, however, is not in doubt: in the United States, Nimbus’s moment passed more than a year ago.

One more reason the timeline matters: some articles you will find under 2026 datelines still claim Nimbus is “now dominant in the US at 43%.” That number is real, but it belongs to June 2025. When you read variant coverage, check the data period and the sample size before you check anything else.

Razor Throat: What It Actually Feels Like

“Razor throat,” or “razor blade throat,” is not a medical term. It is how patients described the sore throat that appeared with the Nimbus wave: a sharp, stabbing, sometimes burning pain, usually at the back of the throat or around the tonsils, that peaks when you swallow. “Sometimes people describe dull achy pain, but other times the pain is ‘sharp.’ Apparently, this new nimbus variant of COVID-19 wreaks enough havoc in the cells of our throats to generate a sharp ‘razor blade’ type of discomfort,” Dr. Michael Lerner, a laryngologist at Yale Medicine, told Everyday Health. One California physician put it more plainly: “Your throat is so dry, so cracked, it’s so painful, it’s even hard to drink sometimes.”

Two honest qualifiers keep this section trustworthy. First, sore throat was already one of the most common COVID symptoms before Nimbus appeared; UCSF’s Dr. Peter Chin-Hong noted that sore throat had been reported in up to 70% of COVID patients even before this variant. Second, experts were careful to say the razor throat link was anecdotal. “The ‘razor blade throat’ is anecdotal and there is no evidence to suggest that this variant leads to more severe sore throat than other variants,” Dr. Scott Roberts of Yale School of Medicine told Healthline. The symptom was striking because of how loud it was, not because it was proven unique to one strain.

The pattern people described, reconstructed from physician reports and patient accounts from the wave, looked like this:

Phase	What people typically reported
Day 1	Scratchy throat, sometimes with fatigue; often dismissed as a cold or allergies
Days 2 to 4	The razor phase: sharp pain on swallowing, difficulty drinking and eating, poor sleep; fever, headache and body aches often join in; congestion and cough may follow
Days 5 to 7	Throat pain eases for most; congestion and fatigue take over as the main complaints
Week 2	Lingering tiredness and a dry cough; a minority report hoarseness or a second throat flare around day 4 before improvement [22]

Why This Sore Throat Hurts So Much

The mechanism is genuinely interesting, and only one ranking page (the archived WebMD piece) explains it. COVID enters cells through ACE2 receptors, and the throat and nose carry more of these receptors than the lower airways do. Research published in The Lancet Infectious Diseases found that among variants circulating in mid-2025, Nimbus bound to ACE2 receptors most strongly. More entry points in the throat means more infected cells there.

But here is the counterintuitive part: the pain is mostly your immune system, not the virus. Once the virus reaches throat tissue, previously primed defenses (from vaccination, past infection, or both) trigger inflammation: fluid buildup, redness, swelling, and nerve irritation. “Symptoms of the sore throat are not from the virus itself,” Dr. Chin-Hong told WebMD. “They are from the inflammatory reaction to the virus.”

Why the throat specifically? Two working ideas from clinicians at the time: the throat is packed with lymphoid tissue full of infection-fighting cells that react vigorously, or the variant simply has a predilection for throat tissue. There is not yet enough data to settle the question, which is itself worth saying out loud. The same uncertainty applies to severity across age groups; whether children experience the razor throat the way adults do was still an open question when the wave passed.

The Full Symptom Picture and How Long It Lasts

Razor throat may have been the headline, but it was never the whole illness. The symptom set physicians and agencies described for the Nimbus wave looked like this:

• Severe sore throat, often the first and loudest symptom
• Fatigue, frequently the symptom that outlasts everything else
• Fever and chills, often moderate in healthy adults
• Headache and body aches
• Congestion or runny nose, sometimes with heavy sinus pressure
• A dry cough that can linger after the throat improves
• Less commonly: nausea, diarrhea, or vomiting
• Rarely now: loss of taste or smell, which has become uncommon across recent variants

Incubation for recent Omicron descendants runs roughly two to five days after exposure, about three to four on average. Most people who described Nimbus infections felt the worst of it around days two to four and improved substantially within a week, with tiredness and cough sometimes hanging on into a second week. For higher-risk people (age 65 and older, chronic lung, heart, or kidney disease, diabetes, obesity, immunocompromise, pregnancy), the same infection carries a different risk profile, and the advice about early testing and a prompt clinician call applies most to them.

Go to emergency care for trouble breathing, persistent chest pain or pressure, new confusion, bluish lips, or trouble staying awake. Beyond emergencies, clinicians flagged these red flags during the wave: throat pain lasting beyond a week, pain much worse than your other symptoms, weight loss, food sticking in the throat, new or worsening shortness of breath, and signs of an obstruction such as drooling, muffled voice, or inability to swallow liquids.

The Testing Trap: Why Razor Throat Reads Negative at First

Here is the practical detail that decides whether your test result means anything. When COVID starts in the throat rather than the nose, home nasal-swab tests can lag behind symptoms. “When throat pain is your only symptom, it can take a few days before nasal swab tests can detect the virus,” Dr. Chin-Hong explained. Patient diaries from the wave match the science: one widely shared day-by-day account described a sore throat on day one, the full razor feeling by day three, and only a faint positive line on day four. Another commenter with classic razor symptoms reported negative home tests while clearly ill.

The practical rules:

1. Symptoms now: test now. A negative result on the first painful day is far from conclusive.

2. Still sick: retest after 24 to 48 hours. That is the standing CDC-consistent advice for repeat testing, and it exists precisely for early, throat-first infections.

3. Positive: trust it. False positives are rare; early false negatives are the real trap.

4. Severe throat pain: also rule out strep. Strep throat is a bacterial infection that needs antibiotics and can lead to serious complications (abscess, rheumatic fever, kidney inflammation) when untreated. A COVID test does not exclude it, and the two can feel almost identical from the outside. “If your sore throat is severe, check in with your doctor to rule out strep throat,” Dr. Roberts advised.

Clue	COVID razor throat	Strep throat
Cause	Virus (SARS-CoV-2)	Bacteria (group A Streptococcus) [3]
Other typical clues	Cough, fatigue, congestion, sometimes loss of taste/smell	Sudden fever, swollen lymph nodes, white patches on tonsils, no cough [3]
Test that identifies it	COVID home test (nose swab)	Rapid strep test or throat culture at a clinic
Treatments	Rest, fluids, symptom relief; antivirals for high-risk patients [4]	Antibiotics, which matter for preventing complications [3]
Why the distinction matters	Avoids unnecessary antibiotics	Prevents rheumatic fever and other sequelae [3]

And since October is a crowded sore-throat month in general, two reference guides make the sorting easier: our side-by-side COVID vs. flu vs. RSV vs. cold symptom chart covers the full respiratory differential, and our Type A flu guide covers the flu side of the season, since flu sore throats can sting too.

How to Treat Razor Throat (and Three Things to Avoid)

There is no cure for the viral infection itself in low-risk adults, but the pain of razor throat is very treatable, and the treatment hierarchy matters more than most lists admit.

Start with systemic pain relief. The most effective approach for a sore throat this intense is whole-body anti-inflammatory medication: ibuprofen or acetaminophen, dosed per the label. [4][8] If swallowing pills is itself the problem, liquid formulations exist for exactly this reason, a small detail that made a big difference for patients who could barely swallow water.

Layer on local relief. Numbing agents such as benzocaine throat sprays and lozenges can buy short-term relief; follow package directions closely, because misuse of benzocaine is dangerous. Menthol lozenges produce a mild numbing effect by quieting nerve activity in the throat. Warm tea with honey, cold treats, ice chips, broths, and small, frequent sips were the hydration advice physicians actually gave (“warm fluids and small sips help,” one put it), and a humidifier can ease the dry, cracked feeling overnight. [8] Honey should never be given to infants under one year old.

Three things to avoid, with reasons:

Don’t push for antibiotics. Antibiotics do nothing to a virus, and overprescribing carries real harms, including disruption of the microbiome and yeast infections. Antibiotics belong only with a confirmed or suspected bacterial cause such as strep.

Don’t reach for steroids for the throat pain. In one 2025 study, people who took a corticosteroid for mild or moderate COVID had longer-lasting symptoms than those who took a nonsteroidal anti-inflammatory, and were more likely to be hospitalized.

Don’t try “throat massage” techniques from social media. The front of the neck carries delicate blood vessels and structures that pressure can injure.

If you test positive and you’re in a higher-risk group, call a clinician the same day: antiviral treatment works best started early in the illness. And if you’re a healthy adult in a household where someone just got sick, there is now a third option this SERP never mentions: in June 2026 the FDA approved XOCOVA (ensitrelvir), the first oral post-exposure preventive pill for household contacts 12 and older, which cut symptomatic COVID risk by 67% in trials when started within 72 hours of the sick person’s first symptoms.

Is Nimbus Still Around in October 2026?

This is the question the ranking pages cannot answer, because they were written before the answer existed. Here it is.

Nimbus is still circulating, but it is no longer the main event in the United States. In the CDC’s estimates for the four weeks ending August 29, 2026, the Stratus-family descendant SW.2 led at about a third of cases, while NB.1.8.1 sat at roughly 3%, comparable to the re-emerged BA.3.2 (“Cicada”) lineage. [14] The late-September nowcast reported by physicians put SW.2 at about 21%, ahead of XFG.1.1 and RW.1.1. Globally, the WHO’s small sequence sample for late July to late August 2026 still had NB.1.8.1 at about a fifth of reported samples, mostly reflecting which countries still sequence at all, and the WHO’s monitoring list dated July 27, 2026 still includes NB.1.8.1.

If you have a sore throat this month, the more likely culprit is the Stratus family, and physicians say that family’s throat symptom is different: scratchy and hoarse, “easily mistaken for allergies,” rather than the razor-blade pain of the Nimbus wave. Reporting on the current season describes this October’s illness as a bad cold with a milder throat than 2025’s. One caveat keeps this honest: with sequencing volumes this low, shares are estimates with wide uncertainty, and “which variant do I have” is not something a home test can tell you anyway.

The Nimbus family also has a next chapter worth knowing: PQ.16.1.1, a descendant of NB.1.8.1 first sequenced on March 25, 2026 and seen mostly in Singapore, was added to the WHO’s Variants Under Monitoring list on July 27, 2026, with the additional public health risk again rated low. A variant fading from one region does not mean its family tree stops growing; it means the surveillance story continues, which is exactly why “check the date on the article you’re reading” is now a survival skill.

For the full picture of what’s circulating this fall, our guides to the SW.2 variant symptoms this October, the newest COVID strain of 2026, and the BA.3.2 Cicada variant cover the rest of the current mix.

Vaccines and Prevention: The 2026-27 Reality

This is where the ranking pages have aged worst. Several still describe vaccine guidance from 2025 or earlier, one recommends a 2023-era booster outright, and none knows about the current season’s shots. The up-to-date picture:

On August 28, 2026, the FDA approved four updated COVID-19 vaccines for the 2026-27 season, formulated against the XFG (Stratus) family that now dominates: products from Moderna, Pfizer-BioNTech, and Novavax/Sanofi. Eligibility this season is narrower than in past years: adults 65 and older, and people 6 months to 64 years with at least one underlying condition that raises their risk of severe COVID. There is no formal national CDC recommendation this season, so practical eligibility questions are best settled with a pharmacist or clinician.

Does a Stratus-adapted shot still cover a Nimbus-family infection? The evidence says yes, comfortably. The WHO said in May 2025 that currently approved vaccines were expected to remain effective against NB.1.8.1 for both symptomatic and severe disease, and European regulator data in 2026 showed post-vaccination neutralizing titers against NB.1.8.1 were only about 1.3-fold lower than against LP.8.1, a small drop in the scale of immune escape. Variants drift; the shots track the family, and severe-disease protection has held across every variant turnover since 2022. For how the current risk actually pencils out, our piece on whether COVID is still serious in 2026 goes deeper.

What Real People Said It Felt Like

The clinical description is one thing. The wave, in patients’ own words from verified June 2025 Reddit threads, is another. These are individual, unverified anecdotes, quoted to show the honest range of experiences, not clinical data.

The pain comparisons were graphic and remarkably consistent. “Easily the worst sore throat I’ve had in my life, I couldn’t even drink water,” one commenter wrote during the first US surge. Another described it “like I had swallowed a bunch of broken glass and it was stuck in my throat,” accompanied at one point by a fever of 104.9 F. Strep comparisons came up again and again: “I thought I had strep throat when I finally got COVID. It was the worst sore throat I’d ever felt, which is how I’ve heard people describe strep.” One veteran of many throat infections put it most memorably: “It felt like someone cut my throat from my uvula down to the bottom of my Adam’s apple. Hurt to breathe, hurt to swallow… I’d rather have strep throat 100/100 times compared to it.”

The desperation hacks were real too. “I had the razor blade sore throat for about four days and at one point I was so desperate that I literally put ice cubes on my neck to numb the inside of my throat,” one patient wrote. “This was by far the worst sore throat I’ve ever had, and I had strep A LOT as a kid.” Another, on the limits of over-the-counter sprays: “nothing eases the pain, the spray burns like hell.”

And the testing trap showed up in the wild exactly as clinicians described: multiple commenters reported classic razor symptoms with negative home tests, one finally turning positive with a faint line on day four, another still negative while clearly ill and reconsidering after day four of no improvement. One person’s GP nurse had already ruled out strep, but the negative COVID test kept them in limbo until they retested. Not everyone was flattened: a few described a few days of sinus and throat misery with fatigue as the worst part, a reminder that the same variant produced anything from a rough weekend to a week in bed.

The pattern in these accounts matches what physicians described then and describe now: throat first and loudest, congestion and fatigue behind it, and severity that depends heavily on your age, immunity, and baseline health.

Frequently Asked Questions

Your realistic next step

If your throat hurts badly right now: take a COVID test today, plan to retest in 24 to 48 hours if it’s negative, and if the pain is severe, add a strep test through a clinician, because those are the two questions a test can actually answer. Meanwhile, ibuprofen or acetaminophen per the label, plus whatever warm or cold fluids you can actually get down, is the evidence-backed way through the worst days. If you’re currently healthy and reading this out of curiosity, the boring moves pay off this season: keep a test kit (or a combo COVID-flu kit) in the cabinet, and if you’re eligible for the updated shot, book it before the winter wave rather than during it.

Sources

World Health Organization, Technical Advisory Group on Virus Evolution, “Initial Risk Evaluation of NB.1.8.1” (May 23, 2025; lineage derivation, earliest sample Jan 22, 2025; VUM designation; spike mutations including position 445 binding; 1.5-1.6-fold neutralization reduction vs LP.8.1.1; low additional risk; vaccines expected effective; 2.5% to 10.7% global share growth; 518 sequences, 22 countries). https://cdn.who.int/media/docs/default-source/documents/epp/tracking-sars-cov-2/23052025_nb.1.8.1_ire.pdf

TODAY.com, “New COVID Variant NB.1.8.1 ‘Nimbus’ Spikes in US: The Top Symptoms” (Aug 4, 2025; first US detection March 2025 via airport screening; 43% of US cases for two weeks ending June 21, 2025; dominant by July; 31 states plus DC; nickname coined by T. Ryan Gregory in late May 2025; CDC precision “low” caveat; Dr. William Schaffner commentary; May 2025 preprint on cell binding). https://www.today.com/health/coronavirus/new-covid-variant-nb181-nimbus-symptoms-rcna212304

Healthline, “‘Razor Blade Throat’: What to Know About the New COVID Variant” (Nancy Schimelpfening, June 19, 2025; Dr. Scott Roberts, Yale: anecdotal symptom, no evidence of more severe sore throat, test to rule out strep; Dr. Kartik Cherabuddi, Tampa General: no significant immune escape or antiviral resistance, no hospitalization increase; red-flag symptoms; strep complications). https://www.healthline.com/health-news/new-covid-variant-nimbus-razor-blade-throat-symptom

WebMD, “Why COVID ‘Razor Blade’ Sore Throat Hurts So Bad” (Julie Stewart, June 26, 2025; Dr. Peter Chin-Hong, UCSF: 70% sore-throat figure, ACE2 receptor density, Lancet Infectious Diseases finding on Nimbus ACE2 binding, pain from inflammatory reaction, systemic therapy, liquid ibuprofen, benzocaine and menthol guidance, steroids study, antibiotic and throat-massage warnings, nasal swab lag; Dr. Matthew Kelly, UAMS). https://www.webmd.com/covid/news/20250626/why-covid-razor-blade-sore-throat-hurts-so-bad

Stony Brook Medicine, “Understanding COVID Nimbus: Symptoms and Key Facts” (Dr. Sharon Nachman, Sept 9, 2025; JN.1-lineage derivation; lab tests show up to 2.5x more efficient cell infection; Stratus comparison; symptom list; emergency warning signs). https://health.stonybrookmedicine.edu/understanding-covid-nimbus-symptoms-and-key-facts/

Medical News Today, “What to know about the Nimbus COVID-19 variant” (Bethany Grayland-Leech, medically reviewed by Angelica Balingit, MD, July 10, 2025; razor-blade sensation and gastrointestinal symptoms; limited research on severity; vaccines effective). https://www.medicalnewstoday.com/articles/nimbus-covid

Everyday Health, “‘Razor Blade’ Sore Throat May Be a Symptom of the New COVID Variant” (June 23, 2025; Dr. Michael Lerner, Yale Medicine laryngologist, on sharp razor-blade pain; Dr. David Wohl, UNC, on lymph-tissue and variant-predilection hypotheses; open question in children). https://www.everydayhealth.com/coronavirus/how-to-cope-with-a-covid-19-sore-throat/

Scripps News, “Emerging Nimbus COVID variant causing ‘razor blade throat’ pain” (June 20, 2025; Dr. Muhammad Azam, Sharp Community Medical Group: dry, cracked, painful throat, hard to drink; warm fluids, small sips, ibuprofen; high infectiousness with otherwise relatively mild course). https://www.scrippsnews.com/health/coronavirus/emerging-nimbus-covid-variant-causing-razor-blade-throat-pain

ABC News, “What to know about COVID variant NB.1.8.1 causing ‘razor blade throat'” (June 20, 2025; GISAID state detections; ACE2 attachment; stable case and hospitalization rates early in the wave). https://abcnews.com/Health/covid-variant-nb181-causing-razor-blade-throat/story?id=123004186

KQED, “COVID is Everywhere (Again) in the Bay Area. What to Know About the Latest XFG ‘Stratus’ Variant” (Aug 27, 2025; Stanford wastewater: Stratus 82%, Nimbus 5.2% locally; Dr. Chin-Hong: Stratus throat is scratchy and hoarse, mistaken for allergies, versus the Nimbus razor throat). https://www.kqed.org/news/12045979/nimbus-nb181-covid-variant-symptoms-razor-blade-throat-incubation-period-testing

The Mirror, “Latest Covid strain spreading through UK could cause new ‘wave of infection'” (July 5, 2025; UKHSA: XFG and XFG.3 about 40% of English cases; Nimbus declining at 7.19%). https://www.mirror.co.uk/news/health/latest-covid-strain-spreading-through-35506520

The Mirror, “WHO’s latest Stratus and Nimbus Covid strain differences and symptoms” (Sept 30, 2025; WHO genomic surveillance: XFG.3 35%, XFG 28%, NB.1.8.1 11%; Stratus primary UK strain). https://www.mirror.co.uk/news/health/whos-latest-stratus-nimbus-covid-35988317

Aurametrix, “Clouds Shift Again: Stratus Dominates, Cicada Stirs” (Jan 3, 2026; US sequencing and wastewater: XFG and descendants 60-70% (about 80% including sublineages by late Dec 2025); Nimbus down to about 5%). https://new.aurametrix.com/2026/01/clouds-shift-again-stratus-dominates.html

Parahealth, “COVID Variants 2026: Symptoms, Current Lineages and Tests” (Luisa Schollek, Oct 3, 2026; secondary tracker compiling: CDC empiric estimates for 4 weeks ending Aug 29, 2026 (SW.2 33%, RV.1 10%, XFG.1.1 8%, BA.3.2 3%, NB.1.8.1 3%, no nowcast); WHO dashboard Jul 26-Aug 23, 2026 (XFG 48.15%, NB.1.8.1 20.37% of 216 sequences); WHO VUM list July 27, 2026 (incl. PQ.16.1.1, earliest Mar 25, 2026, mostly Singapore, low risk); ECDC Sept 25, 2026; RKI week 3, 2026 (NB.1.8.1 52% of 48 German sequences); EMA 2026 (1.3-fold titer reduction vs LP.8.1); nickname origins via Gavi). https://parahealth.com/blogs/blog/alpha-delta-omicron-complete-overview-covid-variants

Parade (via Yahoo Health), “These Are the 7 Most Common Symptoms of the COVID-19 SW.2 Variant Doctors Are Seeing Right Now” (Oct 1, 2026; SW.2 about 21% of US cases in the late-September nowcast; current-season sore throat milder than the 2025 razor-blade wave; Drs. Tyler Evans, William Schaffner; home tests target the stable nucleocapsid; incubation 2-5 days; high-risk early-treatment advice). https://health.yahoo.com/conditions/infectious/coronavirus/articles/7-key-symptoms-covid-19-162500120.html

Nebraska Medicine, “What COVID-19 variants are going around in September 2026?” (Sept 2026; CDC nowcast: SW.2 about 21%, XFG.1.1 about 16%, RW.1.1 about 9%; tests do not identify variants; fewer samples sequenced). https://www.nebraskamed.com/COVID/what-covid-19-variants-are-going-around

MedPage Today, “FDA Approves Four Updated COVID Shots Targeting XFG Variant” (Aug 28, 2026; Moderna, Pfizer-BioNTech, Novavax/Sanofi; eligibility: 65 and older, or 6 months to 64 years with at least one underlying condition). https://www.medpagetoday.com/infectiousdisease/covid19vaccine/122809

Consultant360, “Ensitrelvir (Xocova) Receives FDA Approval for COVID-19 Post-Exposure Prophylaxis” (June 2026; ages 12 and older; SCORPIO-PEP trial, 67% reduction in symptomatic COVID through day 10; start within 72 hours of index case symptom onset). https://www.consultant360.com/fda-alerts/ensitrelvir-xocova-receives-fda-approval-covid-19-post-exposure-prophylaxis

TODAY.com, “Is There a Summer COVID Surge? With Cases Rising in Most States, Watch for These Symptoms” (Sept 22, 2026; current CDC return-to-activity guidance; 48-hour retest advice; current positivity context). https://www.today.com/health/coronavirus/summer-covid-surge-symptoms-guidelines-2026-covid-vaccine-test-rcna592549

Reddit r/Futurology, “Nimbus new Covid variant: Tracking symptoms like ‘razor blade throat’ as NB.1.8.1 spreads in U.S.” (June 14, 2025; individual, unverified patient anecdotes quoted with attribution). https://www.reddit.com/r/Futurology/comments/1lbde56/nimbus_new_covid_variant_tracking_symptoms_like/

Reddit r/news, “New ‘razor blade throat’ COVID subvariant quickly gains ground in California” (June 17, 2025; individual, unverified patient anecdotes quoted with attribution). https://www.reddit.com/r/news/comments/1ldvfac/new_razor_blade_throat_covid_subvariant_quickly/

Reddit r/COVID19positive, “Anyone who had the new Covid variant ‘Nimbus'” (June 28, 2025; individual, unverified patient anecdotes, including the day-by-day diary with a faint day-4 positive and multiple early false negatives). https://www.reddit.com/r/COVID19positive/comments/1lmtiye/anyone_who_had_the_new_covid_variant_nimbus/

Source integrity note: all links were located and verified during research on October 7, 2026 (sources 15 through 19 were verified during the October 5, 2026 SW.2 package and re-confirmed against current reporting). Reddit threads are cited as labeled community anecdotes, not clinical evidence. The Parahealth tracker is a secondary source whose figures are attributed to the CDC, WHO, ECDC, RKI, and EMA in the text.