Influenza Virus Statistics in US 2025 | Flu Facts

Influenza Virus Season in America 2025

The influenza virus season in America during 2025 represents one of the most significant public health challenges in recent years. The 2024-2025 flu season, which extended from September 29, 2024, through August 30, 2025, was classified by the Centers for Disease Control and Prevention as a high severity season, marking the most severe influenza epidemic since the 2017-2018 season. This classification reflects elevated activity across multiple surveillance systems, including outpatient visits, hospitalizations, and deaths. The season’s peak activity occurred during late January and early February 2025, with the national weekly percentage of respiratory specimens testing positive for influenza reaching an unprecedented 31.6% during the week ending February 1, 2025—the highest peak percentage reported in the past nine influenza seasons since 2015-2016.

The impact of the influenza virus on American communities during 2025 has been substantial, affecting millions of individuals across all age groups. Clinical laboratories throughout the United States tested approximately 3,978,954 respiratory specimens for influenza viruses using clinical diagnostic tests during the 2024-2025 season. Of these specimens, 489,579 tested positive, representing a positivity rate of 12.3%. The predominant circulating strain was influenza A, accounting for 88.8% of positive cases (434,985 cases), while influenza B viruses comprised 11.2% (54,594 cases). The geographic distribution of flu activity varied across the ten Health and Human Services regions, with peak activity occurring between late January 2025 and early February 2025 across all regions. Understanding these statistics is crucial for public health planning, resource allocation, and informing vaccination strategies for the current 2025-2026 flu season, which began in fall 2025.

Key Influenza Virus Stats & Facts in the US 2025

Data Source: Centers for Disease Control and Prevention (CDC) FluView Weekly Surveillance Reports, CDC Influenza Activity Report 2024-2025 Season, CDC Flu Burden Estimates 2024-2025

The statistics presented in this comprehensive table demonstrate the unprecedented severity of the 2024-2025 influenza season in the United States. The positivity rate of 12.3% across nearly 4 million specimens tested represents a significant burden of disease, with influenza A viruses clearly dominating the epidemiological landscape at 88.8% of all positive cases. The peak positivity rate of 31.6% during the week ending February 1, 2025, stands as a stark indicator of intense viral transmission during the height of the season. What makes this data particularly concerning is the estimated burden on the healthcare system, with the CDC’s mathematical models projecting between 43 to 47 million symptomatic illnesses across the nation. These projections translate to millions of Americans seeking medical care, with 560,000 to 610,000 hospitalizations placing substantial strain on hospital systems nationwide.

The mortality figures reveal the devastating human toll of the 2025 influenza season, with estimated deaths ranging from 27,000 to 38,000 individuals. Among the most tragic statistics is the 287 laboratory-confirmed pediatric deaths during the 2024-2025 season, representing the highest number of child deaths from influenza ever reported during a seasonal epidemic since pediatric influenza-associated deaths became a nationally notifiable condition in 2004. The cumulative hospitalization rate of 127.1 to 128.1 per 100,000 population marks the highest rate observed since the 2010-2011 flu season, underscoring the exceptional severity of this particular season. The classification as a high severity season across all age groups—the first such designation since 2017-2018—reflects the comprehensive impact of influenza on pediatric, adult, and older adult populations throughout 2025. These facts collectively paint a picture of an influenza season that tested public health infrastructure and highlighted the critical importance of vaccination and antiviral treatment strategies.

Influenza Virus Testing and Laboratory Surveillance in the US 2025

Data Source: CDC FluView Weekly Surveillance Reports 2024-2025, CDC Influenza Hospitalization Surveillance Network (FluSurv-NET)

Laboratory surveillance represents the cornerstone of influenza monitoring in the United States during 2025, providing critical real-time data that guides public health decision-making and resource allocation. The comprehensive testing of nearly 4 million respiratory specimens throughout the 2024-2025 season by clinical laboratories demonstrates the robust surveillance infrastructure established by the CDC and its collaborating laboratories. The 88.8% predominance of influenza A viruses among positive specimens reflects a typical seasonal pattern, though the intensity of circulation was exceptional. Among the influenza A viruses that underwent subtyping, the distribution was remarkably balanced, with A(H1N1)pdm09 comprising 52.5% and A(H3N2) accounting for 47.5% of subtyped viruses. This near-equal distribution of H1N1 and H3N2 strains during the 2025 season contrasts with some previous seasons dominated by a single subtype.

The trajectory of weekly positivity rates throughout the 2025 influenza season reveals the dramatic surge in viral transmission during peak months. Beginning at a baseline of just 0.4% positivity during the summer months of 2024, the rates progressively increased through fall and winter, ultimately reaching the historic peak of 31.6% during the first week of February 2025. This represents the highest peak percentage reported in nine influenza seasons, indicating exceptionally high levels of community transmission. The Influenza Hospitalization Surveillance Network, which covers approximately 9% of the US population across 10 HHS regions, provided geographically representative data that allowed public health officials to track the spread of influenza across different parts of the country. The surveillance data showed that peak influenza activity across all 10 HHS regions occurred within a narrow two-week window between late January and early February 2025, demonstrating synchronized viral transmission across the nation. This laboratory surveillance data formed the foundation for the CDC’s classification of the 2024-2025 season as high severity and informed vaccination recommendations for the upcoming 2025-2026 season.

Influenza Hospitalization Rates in the US 2025

Data Source: CDC Influenza Hospitalization Surveillance Network (FluSurv-NET) 2024-2025, CDC MMWR Weekly Reports

The hospitalization data from the 2024-2025 influenza season in the US reveals the most severe burden on healthcare systems since the 2010-2011 season, with the cumulative hospitalization rate of 127.1 to 128.1 per 100,000 population representing a historic high for the past fourteen years. Between October 1, 2024, and April 30, 2025, the FluSurv-NET surveillance system documented between 38,960 and 39,244 laboratory-confirmed influenza-associated hospitalizations, though actual numbers were likely higher due to reporting delays and cases not captured by the surveillance network covering just 9% of the population. The peak weekly hospitalization rate of 13.5 to 13.6 per 100,000 population, recorded during the week ending February 8, 2025, tied with the 2017-2018 season as the highest peak weekly rate observed across all seasons since 2010-2011, demonstrating the intense pressure on hospital systems during the height of the epidemic.

Age-stratified hospitalization data reveals stark disparities in influenza-related severe outcomes across different demographic groups during 2025. Adults aged 75 years and older experienced by far the highest cumulative hospitalization rate at 598.8 per 100,000 population—more than fifteen times higher than the rate observed in children aged 5-17 years, who had the lowest rate at 39.3 per 100,000. This dramatic age gradient underscores the heightened vulnerability of elderly populations to severe influenza complications requiring hospitalization. Across all age groups, hospitalization rates during the 2024-2025 season were 1.8 to 2.8 times higher than median rates observed from the 2010-2011 through 2023-2024 seasons, indicating that every age demographic experienced substantially elevated risk during this particular season. The virus type distribution among hospitalizations showed influenza A viruses accounting for the vast majority at 95.8% to 97.4% of cases (37,602 hospitalizations), while influenza B represented only 3.8% (1,492 hospitalizations). The synchronization of peak hospitalization activity across all age groups during the week ending February 8, 2025, placed unprecedented simultaneous demands on hospital resources nationwide, highlighting the importance of surge capacity planning in healthcare systems for future influenza seasons.

Influenza Mortality and Pediatric Deaths in the US 2025

Data Source: CDC Influenza-Associated Pediatric Mortality Surveillance System, CDC Flu Burden Estimates, CDC FluView Weekly Reports

The mortality statistics from the 2024-2025 influenza season in the United States represent one of the most sobering aspects of this high-severity epidemic, with the CDC estimating that between 27,000 and 38,000 deaths occurred as a result of influenza during the season. These estimates, derived from mathematical modeling based on hospitalization data from the FluSurv-NET surveillance network, fall within the historical range of annual influenza-related deaths observed from 2010 to 2024, which varied from 6,300 to 52,000 deaths depending on season severity. However, what distinguishes the 2024-2025 season is not just the total mortality burden, but particularly the devastating impact on children. The 287 laboratory-confirmed influenza-associated pediatric deaths reported during the season represent the highest number ever recorded since pediatric influenza deaths became a nationally notifiable condition in 2004, surpassing even the previous high of 207 deaths during the 2023-2024 season and far exceeding the low of 37 deaths during the 2011-2012 season.

Analysis of the pediatric mortality data reveals critical patterns that underscore the importance of vaccination and risk factor management in children during 2025. Among the 207 children who were eligible for influenza vaccination and had known vaccination status, an alarming 89.4% (185 children) were not fully vaccinated against influenza at the time of their death. This statistic powerfully demonstrates the protective value of vaccination, as the vast majority of pediatric deaths occurred in unvaccinated children. Additionally, among the 260 children and adolescents with known medical history, 56.5% (147 children) had at least one underlying medical condition associated with higher risk for developing serious influenza-related complications, including conditions such as asthma, diabetes, neurological disorders, and immunocompromising conditions. The deaths were predominantly associated with influenza A viruses, reflecting the overall predominance of influenza A during the season. As the 2025-2026 influenza season began in fall 2025, surveillance through the week ending November 8, 2025, showed zero pediatric deaths reported for the new season, though health officials remained vigilant given the severe impact observed during the previous year. These mortality statistics serve as a powerful reminder of influenza’s potential lethality and the critical importance of annual vaccination for all eligible individuals, particularly children and those with underlying health conditions.

Influenza Vaccination Coverage in the US 2025

Data Source: CDC FluVaxView Dashboard, CDC National Immunization Survey (NIS-Flu and NIS-ACM), CDC Vaccine Safety Datalink

Vaccination coverage during the 2024-2025 influenza season in the US revealed concerning gaps in population protection despite the availability of 147.6 million doses distributed throughout the season. The coverage data shows substantial variation across different demographic groups, with older adults aged 65 years and above achieving the highest vaccination rate at 71%, while adults aged 18-49 years had the lowest coverage at just 35%. This disparity in uptake is particularly concerning given that working-age adults can serve as key transmitters of influenza within communities and to more vulnerable populations. Pediatric vaccination coverage of 49.2% as of April 26, 2025, represented a decline from the previous season’s 53.4%, contributing to the heightened burden of pediatric influenza deaths. The drop in childhood vaccination rates during 2025 reflects broader trends of vaccine hesitancy and reduced healthcare-seeking behavior that public health officials have observed in recent years.

Among pregnant women, vaccination coverage remained virtually unchanged from the previous year at 38.0% as of March 29, 2025, compared to 38.1% in 2024—a rate that public health experts consider suboptimal given the increased risks that influenza poses to pregnant women and their infants. Significant racial and ethnic disparities exist in vaccination uptake among pregnant women, with Non-Hispanic Asian pregnant women achieving the highest coverage at 53.1%, while Non-Hispanic Black pregnant women had the lowest coverage at 26.4%, representing a gap of nearly 27 percentage points. These disparities highlight the need for targeted outreach and culturally competent vaccination promotion strategies. Looking forward to the 2025-2026 season, vaccine manufacturers have projected supply of up to 154 million doses, with 121 million doses already distributed as of November 8, 2025. The 2025-2026 vaccines are trivalent formulations designed to protect against three main seasonal influenza viruses: an A(H1N1) virus, an A(H3N2) virus, and a B/Victoria lineage virus. Vaccine effectiveness studies from the 2024-2025 season demonstrated that vaccination reduced the risk of influenza-associated illness by 37% to 56% in outpatient settings and 39% to 62% in inpatient settings, depending on age group. The CDC estimates that vaccination during the 2024-2025 season prevented between 9.4 and 16 million symptomatic illnesses, 4.4 to 7.1 million medical visits, 170,000 to 360,000 hospitalizations, and 12,000 to 39,000 deaths, underscoring the substantial public health benefit of achieving higher vaccination coverage rates during 2025 and beyond.

Influenza Virus Strains Circulating in the US 2025

Data Source: CDC Influenza Virologic Surveillance System, CDC Antigenic Characterization Data, CDC Genetic Analysis Reports

The virologic landscape of the 2024-2025 influenza season in the United States was characterized by the clear predominance of influenza A viruses, which accounted for 88.8% of all positive specimens (434,985 cases), while influenza B viruses comprised 11.2% (54,594 cases). Among the influenza A viruses that underwent subtyping, there was a remarkably balanced distribution between the two main seasonal subtypes: A(H1N1)pdm09 viruses comprised 52.5% and A(H3N2) viruses accounted for 47.5% of subtyped specimens. This near-equal co-circulation of both H1N1 and H3N2 strains throughout the 2025 season is notable, as many recent seasons have been dominated by one subtype or the other. The temporal pattern showed influenza A activity peaking at 30.4% positivity in late January 2025, contributing to the intense surge in cases and hospitalizations during the winter months.

The influenza B viruses detected during the 2024-2025 season in the US all belonged exclusively to the B/Victoria lineage, with no detections of B/Yamagata lineage viruses. The B/Yamagata lineage has not been identified globally since March 2020, leading to the transition to trivalent vaccines that no longer include a B/Yamagata component. Genetic analysis revealed that all 902 influenza B viruses characterized belonged to genetic clade V1A.3a.2, which was the same clade included in the 2024-2025 Northern Hemisphere influenza vaccines. Within this clade, 9 distinct subclades were identified co-circulating during the season, including C.3, C.3.1, C.3.2, C.5, C.5.1, C.5.5, C.5.6, C.5.6.1, and C.5.7. While subclades C.5, C.5.1, C.5.6, and C.5.7 predominated at the beginning of the season, subclade C.3.1 increased in proportion and became one of the major co-circulating subclades after March 2025. Antigenic characterization testing demonstrated that 84.9% of B/Victoria viruses were well-recognized by antisera raised against the vaccine reference virus, with antibody titers within 4-fold of the reference, indicating good vaccine match. Influenza B activity peaked much later than influenza A, reaching 4.3% positivity in late March 2025, contributing to the extended duration of the flu season. This genetic and antigenic surveillance data informed the selection of vaccine components for the 2025-2026 Northern Hemisphere influenza vaccines, ensuring optimal match with circulating strains for the upcoming season.

Regional Influenza Activity Patterns in the US 2025

Data Source: CDC FluView Regional Surveillance Data, CDC HHS Regional Reports

The geographic distribution of influenza activity across the United States during the 2024-2025 season demonstrated remarkable temporal synchronization, with all 10 HHS regions experiencing peak activity within a narrow two-week window between late January and early February 2025. This synchronized peak across diverse geographic regions—from New England to the Pacific Northwest, from the Southeast to Alaska—indicates widespread and intense community transmission of influenza viruses throughout the nation during the winter months of 2025. Regions 4 (Southeast), 6 (South Central), 7 (Central), and 9 (West Coast) reached their peak activity during the week ending January 25 or February 1, 2025, slightly earlier than other regions. Regions 1 (New England), 2 (New York/New Jersey/Puerto Rico), 3 (Mid-Atlantic), 8 (Mountain), and 10 (Pacific Northwest) peaked during the week ending February 1 or February 8, 2025. Regions 5 (Midwest) and 7 (Central) experienced their peak latest, during the week ending February 15, 2025.

The cumulative hospitalization rates varied substantially by region during 2025, ranging from 117.8 to 218.3 per 100,000 population across the 10 HHS regions, reflecting differences in population demographics, healthcare access, underlying health conditions, and vaccination coverage. Despite these variations in cumulative burden, the synchronization of peak timing suggests that the dominant influenza strains circulating during the 2024-2025 season had similar transmissibility characteristics across different climatic zones and population densities. This pattern differs from some previous seasons where activity peaked earlier in southern states and progressively moved northward. The national peak of 31.6% positivity during the week ending February 1, 2025, represented the convergence of high activity levels across all regions simultaneously, placing unprecedented coordinated demands on healthcare systems, emergency departments, and intensive care units nationwide. The relatively brief two-week window during which all regions experienced their peaks underscores the explosive nature of transmission during this high-severity season and highlights the importance of early vaccination before influenza activity intensifies in communities. As the 2025-2026 season began in fall 2025, public health officials across all regions remained vigilant, using the lessons learned from the severe 2024-2025 season to strengthen surveillance systems, promote earlier vaccination, and prepare healthcare systems for potential surges in demand.

Influenza Antiviral Treatment and Resistance in the US 2025

Data Source: CDC Antiviral Susceptibility Testing 2024-2025, CDC Influenza Antiviral Medications Guidelines, CDC Virologic Surveillance

Antiviral medications represent a critical second line of defense against influenza in the United States during 2025, complementing vaccination efforts for both treatment and prevention of severe disease. During the 2024-2025 season, there were 4 FDA-approved antiviral drugs recommended by the CDC for treating flu: three neuraminidase inhibitors (oseltamivir, zanamivir, and peramivir) and one polymerase acidic endonuclease inhibitor (baloxavir). Surveillance data from the season showed that nearly all circulating seasonal influenza A and B viruses remained susceptible to these neuraminidase inhibitors and to baloxavir, indicating that antiviral resistance has not emerged as a significant clinical problem during 2025. This maintained susceptibility is crucial for ensuring that antivirals remain effective therapeutic options for treating severe influenza cases and providing post-exposure prophylaxis for high-risk individuals. The standard treatment regimen for oseltamivir, the most commonly prescribed antiviral, is 75 mg twice daily for 5 days, though higher doses or longer durations may be considered for severely immunocompromised patients or those with severe disease.

The timing of antiviral treatment initiation is critical to maximizing clinical benefit during 2025. Studies have consistently demonstrated that flu antiviral drugs work best when started within 48 hours of symptom onset, reducing illness duration by approximately one day and decreasing the risk of complications requiring hospitalization. For patients hospitalized with influenza, early antiviral treatment has been shown to reduce both the duration of hospitalization and the risk of death, making prompt initiation essential for those with severe disease. Clinical effectiveness studies show that when used for chemoprophylaxis (prevention), oseltamivir, zanamivir, and baloxavir have been approximately 70-90% effective in preventing influenza caused by susceptible strains.

Disclaimer: This research report is compiled from publicly available sources. While reasonable efforts have been made to ensure accuracy, no representation or warranty, express or implied, is given as to the completeness or reliability of the information. We accept no liability for any errors, omissions, losses, or damages of any kind arising from the use of this report.

Email ID:

Please enable JavaScript in your browser to complete this form.

Email

Email *

SUBSCRIBE