Flu (influenza)

Infections. Also called: Influenza, Flu.

How common is Flu (influenza) in the US?

Estimated cumulative influenza-associated hospitalization rate for the 2025-2026 season: 80.0 per 100 000 (US population (cumulative influenza hospitalization rate per 100,000); United States, October 1, 2025 through March 14, 2026 (2025-2026 influenza season, interim)). Source: JAMA Network Open (CDC), 2026. Label: MODELED.

• 80.0 per 100 000 Estimated cumulative influenza-associated hospitalization rate for the 2025-2026 season. Out of: US population (cumulative influenza hospitalization rate per 100,000). Where: United States. When: October 1, 2025 through March 14, 2026 (2025-2026 influenza season, interim). Cumulative hospitalization rate from FluSurv-NET-based burden model; not overall illness incidence, and season data are interim (through March 14, 2026). Label: MODELED.

  The estimated cumulative influenza-associated hospitalization rate was 80.0 per 100 000 which would correlate with estimates of between 28 000 000 to 49 000 000 illnesses, 360 000 to 740 000 hospitalizations, and 22 000 to 74 000 deaths in the US during the 2025-2026 season.

  Source: Influenza Activity and Estimated Vaccine Effectiveness During the 2025-2026 Influenza Season JAMA Network Open (CDC), 2026. PubMed 42307948. DOI 10.1001/jamanetworkopen.2026.18581.

Each figure measures something different. Do not compare them with each other or with other conditions.

Medical codes

• ICD-10-CM FY2026: J11.1 Influenza due to unidentified influenza virus with other respiratory manifestations (narrower). Other codes in this category also apply.
• ICD-10-CM FY2026: J10.1 Influenza due to other identified influenza virus with other respiratory manifestations (narrower). Other codes in this category also apply.

Research activity

As of 2026-09-24: 2,802 registered studies on ClinicalTrials.gov (search Influenza) and 29,827 PubMed records, 2021 to 2025. A count of records is not how common or serious the condition is.

Population information, not medical advice. Methodology · Known limitations