The dominant COVID strain circulating right now is XFG, which accounts for about 29% of sequenced cases in the United States as of mid-February 2026. It’s joined by NB.1.8.1 at 21% and XFG.2.5.1 at 16%. Together, the XFG family and its sublineages make up roughly 65% of all circulating virus, making it the clear frontrunner this season.
The Strains Circulating Right Now
CDC genomic surveillance data shows a landscape dominated by XFG and its offshoots. Here’s how the current mix breaks down:
- XFG: 29%
- NB.1.8.1: 21%
- XFG.2.5.1: 16%
- XFG.1.1: 9%
- XFG.14.1: 7%
- XFZ: 5%
- PQ.17: 4%
- XFG.6: 4%
All of these are descendants of the Omicron lineage, which has been the backbone of COVID evolution since early 2022. The “XF” prefix indicates recombinant variants, meaning they formed when two different sublineages swapped genetic material inside the same infected person. This recombination is one reason newer strains can outcompete older ones so quickly. They inherit useful mutations from both parent lineages at once, rather than accumulating them one at a time.
Why These Strains Took Over
New variants rise to dominance for two main reasons: they spread more easily, or they dodge the immune protection people already have. The current crop does both. Research on earlier recombinant variants like XEC showed that their hybrid genetic makeup gives them a fitness advantage over predecessors, enabling faster person-to-person spread. Key mutations also help the virus slip past antibodies generated by previous infections or vaccinations, a trait called immune evasion.
This pattern has repeated itself since Omicron first appeared. Each wave’s dominant strain eventually loses ground to a newer subvariant that spreads a little faster or evades immunity a little better. The decline of earlier strains like KP.3.1.1 followed this exact playbook, displaced by variants with superior adaptability.
Symptoms to Expect
The symptom list for current strains remains broadly similar to what most people experienced with earlier Omicron waves. Common symptoms include fever or chills, cough, sore throat, congestion or runny nose, fatigue, muscle aches, and headache. Some people also report nausea, vomiting, or diarrhea. Loss of taste or smell still occurs but is less frequent than it was with pre-Omicron variants.
Symptoms typically appear 2 to 14 days after exposure and often start mild before potentially worsening. The CDC notes that symptoms can vary depending on vaccination status, and the specific mix of symptoms may shift slightly with each new variant. For most vaccinated or previously infected people, the illness resembles a moderate cold or flu lasting about a week.
How Severe Is This Wave?
Overall severity has remained relatively stable across variant periods. Hospital data comparing pre-Delta, Delta, and Omicron eras found no statistically significant differences in ICU admission rates among hospitalized patients, which held steady around 20 to 21%. In-hospital death rates actually trended slightly lower during the Omicron era (0.4%) compared to Delta (0.9%).
CDC modeling for the current respiratory season projects peak COVID hospitalization rates between roughly 4 and 6 hospitalizations per 100,000 people per week if no major immune-escaping variant emerges. If one does, that number could climb to 7 to 9.5 per 100,000. Either way, the agency expects total respiratory disease hospitalizations this season to land within 20% of last year’s numbers. The national hospitalization peak typically hits in late December or early January.
How Well Rapid Tests Work
Home rapid antigen tests still detect current variants, but their sensitivity depends heavily on timing. Compared against the gold-standard PCR test, rapid tests catch only about 47% of infections overall. That number jumps to 56% on days you have symptoms and reaches 77% on days you have a fever. The sweet spot for testing is about 2 to 3 days after symptoms start, when the percentage of positive rapid tests peaks around 59 to 65%.
If you have no symptoms, rapid tests perform poorly, catching only about 18% of PCR-confirmed infections. The practical takeaway: test once symptoms appear, ideally when you have a fever, and consider retesting a day or two later if your first result is negative but you still feel sick.
Vaccine Protection Against Current Strains
Updated COVID vaccines continue to reduce the risk of hospitalization, though their effectiveness varies depending on how closely the vaccine formula matches circulating strains. The KP.2-adapted vaccine showed 68% effectiveness against hospitalization in a case-control study. Earlier XBB.1.5-adapted vaccines provided about 46 to 50% protection against hospitalization in adults, dropping to around 37% in immunocompromised adults. Effectiveness also declined when the circulating virus drifted further from the vaccine target, falling to 14 to 54% during the JN.1 wave.
This pattern is why vaccine formulas get updated. As circulating strains evolve away from the version the vaccine was designed around, protection fades. Each updated shot aims to close that gap.
Treatment Still Works
Antiviral treatment taken within five days of diagnosis reduced hospitalization risk by 39% during a study period spanning multiple Omicron subvariants from 2022 through 2023. That’s lower than what early clinical trials showed, which is expected in real-world conditions where patients have varying levels of prior immunity and underlying health. The key finding is that antivirals remained effective across Omicron subvariants rather than losing potency as the virus evolved, which is encouraging for the current strains as well.
What to Expect This Season
CDC scenario modeling projects two periods of increased COVID activity: a first peak in late August 2025 and a second, typically larger peak in January 2026. COVID hospitalizations during fall and winter have consistently peaked in late December or early January in recent years. This timing overlaps with influenza (which peaks between December and February) and RSV (late December to early January), meaning the overall burden on hospitals concentrates in a narrow winter window.
The wild card is whether a new variant with significant immune-escape properties emerges during fall. If one does, modeling suggests the winter hospitalization peak could be roughly 50 to 75% higher than the baseline scenario. The CDC rates the overall season outlook with low to moderate confidence, reflecting the inherent unpredictability of viral evolution.