Influenza
Seasonal flu causes recurring outbreaks every year, while flu strains that jump from animals to people are watched closely for pandemic risk.
Snapshot: 9/21/2026, 4:31:19 PM · 12 tracked locations · 103,978 active cases (dataset)
At a glance
Quick facts
- How it spreads
- Droplets and aerosols; high-transmission settings include schools, long-term care facilities, and mass transit during peaks.
- How serious
- About 0.0 of every 100 confirmed cases died
- Where it's active
- Highest current burden: United States (US) and Japan (JP).
- Vaccine / treatment
- Annual vaccines, antiviral treatment per guidelines, respiratory etiquette, and workplace sick leave policies.
Important
Virus Tracker provides aggregated outbreak monitoring for education and situational awareness. It is not medical advice, a diagnostic service, or a substitute for guidance from qualified health professionals or official public health agencies. Always consult licensed clinicians and authoritative sources for personal health decisions.
Overview
Influenza A and B drive winter burdens in temperate zones and more complex seasonality in tropics. Vaccination composition updates follow antigenic drift surveillance. Virus Tracker visualizes regional pressure proxies where open metrics align with syndromic or laboratory reporting.
Transmission
Droplets and aerosols; high-transmission settings include schools, long-term care facilities, and mass transit during peaks.
Symptoms & clinical notes
Fever, cough, myalgia, and malaise; complications include pneumonia especially in elderly and high-risk groups.
Prevention & control
Annual vaccines, antiviral treatment per guidelines, respiratory etiquette, and workplace sick leave policies.
Surveillance context
Sentinel clinics, lab networks, and global sharing platforms inform vaccine strain selection.
Live dataset
Key metrics
Active cases
104K
Deaths
2.5K
How fast it's spreading
0.7%
RisingInfluenza — global infection heat map
Country shading reflects relative active-case intensity from the current Virus Tracker dataset for this pathogen. Hover countries on desktop for counts.
Darker red = more people currently sick.
Live dataset
Trajectory outlook
Projected case trend with a modeled confidence range.
Projected case trajectory for Influenza, with a shaded confidence range, based on the current Virus Tracker dataset.
Live dataset
Top regions by active cases
The 10 tracked locations with the most active Influenza cases in the current dataset.
Top 10 tracked locations for Influenza by active cases, ranked highest to lowest.
Live dataset
Threat intelligence visuals
Threat matrix
How fast vs. how deadly
Each bubble is a threat. Bigger bubbles mean more people are currently sick.
Where this data comes from
11 of 15 sources are reporting normally.
- 11 healthy sourcesHealthy
- 4 sources downDown
- Data reliability
- 86%
- Confidence-adjusted exposure
- 78.5K
Overall threat level
Where it's hitting hardest
- Japan29.3K active · score 21.3
- United States74.2K active · score 13.1
Dataset
Top affected regions
| Location | Active | Deaths | Trend |
|---|---|---|---|
| United States (US) | 37,361 | 0 | Stable |
| Japan (JP) | 29,256 | 2,501 | Rising |
| HHS Region 4 (Atlanta), United States | 11,729 | 0 | Stable |
| HHS Region 9 (San Francisco), United States | 8,256 | 0 | Stable |
| HHS Region 3 (Philadelphia), United States | 3,864 | 0 | Rising |
| HHS Region 2 (New York), United States | 3,190 | 0 | Rising |
| HHS Region 5 (Chicago), United States | 3,183 | 0 | Rising |
| HHS Region 6 (Dallas), United States | 2,224 | 0 | Falling |
| HHS Region 10 (Seattle), United States | 1,880 | 0 | Rising |
| HHS Region 1 (Boston), United States | 1,449 | 0 | Rising |
| HHS Region 8 (Denver), United States | 1,103 | 0 | Falling |
| HHS Region 7 (Kansas City), United States | 483 | 0 | Rising |
Frequently asked questions
How does the flu spread?
Mainly through droplets released when an infected person coughs, sneezes, or talks nearby, and by touching contaminated surfaces then the face.
Is the flu vaccine worth getting every year?
Yes. Flu viruses change often, so vaccines are updated annually to match circulating strains and reduce the risk of severe illness.
Who is most at risk of severe flu?
Young children, older adults, pregnant women, and people with chronic health conditions face the highest risk of complications like pneumonia.
Is this page medical advice?
Virus Tracker provides aggregated outbreak monitoring for education and situational awareness. It is not medical advice, a diagnostic service, or a substitute for guidance from qualified health professionals or official public health agencies. Always consult licensed clinicians and authoritative sources for personal health decisions.
What does "outbreak activity" mean on Virus Tracker?
Outbreak activity reflects active-case burden relative to recoveries in our models. It helps compare stressed outbreak zones within the dataset—it is not a clinical score.
How often is this wiki updated?
Figures refresh on the site’s ingestion and revalidation schedule (typically about every 30 minutes in production). Timestamps on the dashboard snapshot indicate the last build of the underlying dataset.
Why might the heat map not match official government totals?
We merge multiple open sources and fallbacks; reporting lag, testing policy, and geographic coverage differ by country. Use national health ministries for authoritative case definitions.
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