Several bugs are circulating right now, with influenza leading the pack. As of late February 2026, flu test positivity sits at 15.8%, making it the dominant respiratory illness in the United States. RSV (respiratory syncytial virus) follows at 9.1%, COVID-19 is at 3.8%, and norovirus (the “stomach bug”) continues its winter surge with 644 reported outbreaks since August 2025.
Influenza Is the Biggest Player Right Now
Flu is responsible for more positive tests than any other respiratory virus this season. Two strains of influenza A have been co-circulating at nearly equal levels: H1N1 accounts for about 53% of subtyped cases and H3N2 makes up the remaining 47%. That even split is unusual. Most seasons, one strain dominates and the other plays a minor role.
Flu typically hits hardest from December through February, so the current wave is right on schedule. Classic flu symptoms include a high fever (often 100 to 102°F), body aches that can feel severe, fatigue that lingers for up to three weeks, headache, and a cough that worsens over time. If you feel like you’ve been hit by a truck, it’s more likely flu than a common cold.
RSV Is Still Elevated
RSV positivity is running at 9.1%, which means it’s still a significant presence even as its winter peak begins to taper. RSV tends to cause the most trouble at the extremes of age. In babies and toddlers, it can lead to wheezing, rapid breathing, and difficulty feeding. In adults over 65, it can trigger serious lower respiratory infections. For healthy adults in between, RSV often looks and feels like a bad cold with heavy congestion and a persistent cough.
COVID-19 Is Circulating at Low Levels
At 3.8% positivity, COVID-19 is present but far less dominant than flu or RSV right now. The symptoms still overlap heavily with flu: fever, headache, body aches, cough, sore throat, and fatigue. The most distinctive marker of COVID remains loss of taste or smell, which is uncommon with other respiratory viruses. That said, newer variants don’t always cause this symptom, so a test is the only reliable way to tell COVID apart from flu.
Norovirus Is Driving the Stomach Bug Wave
If what’s going around your household involves vomiting, diarrhea, and stomach cramps rather than coughing and sneezing, norovirus is the likely culprit. The CDC has logged 644 norovirus outbreaks since August 2025, and the virus peaks between December and March, meaning this is its most active window.
Norovirus moves fast. The incubation period is just 12 to 48 hours after exposure, and symptoms tend to be intense but short-lived, resolving in one to three days for most people. The biggest risk is dehydration, especially in young children and older adults. It spreads through contaminated food, surfaces, and close contact with someone who’s sick, and it’s notoriously hard to kill on surfaces. Alcohol-based hand sanitizer doesn’t reliably destroy it. Soap and water is better.
Walking Pneumonia in Younger Children
A bacterial infection called Mycoplasma pneumoniae has been elevated since late spring, particularly in children. This is the organism behind “walking pneumonia,” a milder form of pneumonia where people feel sick but can usually still go about their day. It causes a persistent dry cough, low-grade fever, fatigue, and sometimes a sore throat or headache.
What’s different this time is the age group affected. Walking pneumonia historically shows up most in school-age kids (5 to 17) and young adults. The current wave is hitting children ages 2 to 4 at rates not typically seen. The percentage of hospital discharge diagnoses tied to this infection jumped from 1.0% to 7.2% among 2-to-4-year-olds and from 3.6% to 7.4% among 5-to-17-year-olds. Because it’s bacterial, it responds to antibiotics, unlike viral respiratory infections.
How to Tell What You Have
The overlap between respiratory viruses makes self-diagnosis tricky, but a few patterns help narrow things down. A cold tends to stay mild: runny nose, congestion, maybe a sore throat, but rarely a fever or significant body aches. Flu comes on suddenly with a high fever, severe body aches, and exhaustion that knocks you flat. COVID looks similar to flu but may include loss of taste or smell. RSV leans heavily toward congestion, wheezing, and cough without the full-body misery of flu.
If your symptoms center on your gut (nausea, vomiting, watery diarrhea) rather than your respiratory system, norovirus is the most likely explanation. And a dry cough that drags on for weeks without much fever could point toward walking pneumonia, especially in kids.
Home tests for COVID and flu are widely available at pharmacies if you want a quick answer. For anything involving a child under two months with a fever, difficulty breathing at any age, or symptoms that worsen after initially improving, getting evaluated in person is the right move.
Protecting Yourself This Season
Updated vaccines exist for the three major respiratory viruses. The 2024-2025 flu vaccine covers three influenza strains and is recommended for everyone six months and older. The updated COVID-19 vaccine is similarly recommended for everyone six months and older. For RSV, protection depends on your age: adults 75 and older are recommended a single dose, as are adults 60 to 74 with risk factors for severe disease. If you received an RSV vaccine last year, you don’t need another one.
Babies under 8 months can be protected against RSV either through maternal vaccination during pregnancy (given at 32 to 36 weeks) or through an antibody injection given at birth or before RSV season. Some children between 8 and 19 months at higher risk also qualify for the antibody treatment.
For norovirus, there’s no vaccine available. Frequent handwashing with soap and water, disinfecting surfaces with bleach-based cleaners, and keeping sick household members isolated as much as possible are the best defenses. The virus remains contagious for a couple of days after symptoms resolve, so don’t rush back to shared spaces too quickly.
Managing Symptoms at Home
Most of these illnesses resolve on their own with rest and fluids. For fevers above 102°F that are causing discomfort, acetaminophen or ibuprofen can help, though it typically takes one to two hours to feel the effect. For low-grade fevers, medication isn’t always necessary since fever is part of how your body fights infection. Children should never be given aspirin due to the risk of a rare but serious condition called Reye’s syndrome.
With norovirus, the priority is staying hydrated. Small, frequent sips of water or an electrolyte drink work better than trying to gulp down large amounts at once. For respiratory viruses, a humidifier, saline nasal spray, and throat lozenges address the most annoying symptoms while your immune system does the real work.