Yes, the flu is actively circulating across the United States. The 2025-26 flu season is well underway, and CDC surveillance data through late January 2026 showed a cumulative hospitalization rate of 59.5 per 100,000 people, the highest at that point in the season since 2010-11. Flu activity in the U.S. typically peaks between December and February, so much of the country is in or near the worst stretch right now.
How Bad Is This Flu Season?
This season has been notably severe. The hospitalization rate of 59.5 per 100,000 recorded through the last week of January 2026 stands out as the highest for that week in over a decade. Children have been hit especially hard: the cumulative pediatric hospitalization rate is the second highest since 2010-11. For context, the 2024-25 season that preceded this one saw 280 flu-related pediatric deaths nationwide, a rate of 3.8 per million children.
Two strains of influenza A are driving nearly all the illness. During the prior 2024-25 season, about 94% of positive flu tests were influenza A, with the remainder being influenza B. Among the influenza A viruses, the H1N1 strain made up 53% and the H3N2 strain accounted for 47%, meaning both were circulating in roughly equal measure rather than one dominating.
When Does Flu Season Peak?
Looking at four decades of CDC data, February is the most common peak month for flu activity, with 18 out of 42 seasons peaking then. December and January are the next most common, followed closely by March. That means if you’re reading this in midwinter, you’re likely in or near the highest-risk period. Flu viruses circulate year-round at low levels, but the concentrated wave of illness runs from roughly October through April, with the sharpest spike in that December-to-February window.
Activity doesn’t shut off after the peak. It declines gradually, so you can still catch the flu well into March or April. Six seasons out of the last 42 peaked as late as March.
Flu vs. COVID vs. a Cold
Several respiratory viruses circulate at the same time each winter, and the symptoms overlap enough to cause confusion. Here’s how to tell them apart:
- Fever and body aches: The flu almost always causes both. A common cold rarely causes fever and essentially never causes muscle aches. COVID usually causes fever and sometimes causes body aches.
- Loss of taste or smell: This is a hallmark of COVID, especially early in the illness, and it often shows up without a stuffy nose. The flu rarely causes it, and colds don’t.
- How fast it hits: Flu symptoms tend to come on suddenly, typically one to four days after exposure. COVID has a wider incubation window of 2 to 14 days.
- Digestive symptoms: Diarrhea sometimes accompanies the flu, particularly in children. It’s less typical of COVID and more associated with colds.
- Shortness of breath: Both flu and COVID can cause it. A cold doesn’t.
Testing is the only reliable way to confirm which virus you have, and it matters because the treatments are different.
How Well Does the Vaccine Work?
Flu vaccine effectiveness varies by age group and setting. Interim CDC estimates from the 2024-25 season found that among children and teens, the vaccine reduced the risk of outpatient flu illness by 32% to 60%, depending on the study network. Protection against hospitalization was stronger: 63% to 78% in children.
For adults, outpatient effectiveness ranged from 36% to 54%, and protection against hospitalization was 41% to 55%. Those numbers may sound modest compared to some other vaccines, but even partial protection can mean the difference between a rough week at home and a hospital stay. The vaccine tends to perform better at preventing serious illness than at preventing any illness at all.
If you haven’t been vaccinated yet this season, it can still offer protection as long as flu viruses are circulating, which they will be for weeks to come.
Antiviral Treatment Timing
Prescription antiviral drugs can shorten the duration of flu symptoms and reduce the risk of complications, but they work best when started within one to two days of symptom onset. That narrow window is why getting tested early matters. Four antiviral medications are currently approved and recommended by the CDC for treating the flu.
Some are taken as pills, others as inhaled powder or a single intravenous dose. Your doctor will choose based on your age, health conditions, and how severe your symptoms are. The key takeaway is speed: if you develop sudden fever, body aches, and cough during flu season, getting evaluated within 48 hours gives you the best shot at effective treatment.
Who Faces the Highest Risk
This season’s hospitalization data reinforces what’s true every year: young children, older adults, pregnant people, and those with chronic health conditions like asthma, diabetes, or heart disease face the greatest risk of severe flu complications. The pediatric hospitalization rate this season being near historic highs is a reminder that healthy children aren’t immune to serious outcomes.
People 65 and older consistently account for the largest share of flu hospitalizations and deaths in most seasons. If you or someone in your household falls into a higher-risk group, prompt testing and early antiviral treatment become especially important during the weeks when flu activity is at its highest.