Influenza Rates by State in US 2025 | Statistics & Facts

Influenza Rates by State in US 2025

The 2025-2026 influenza season in the United States has emerged as a significant public health concern, with seasonal influenza activity continuing to increase across the country as of December 2025. According to the Centers for Disease Control and Prevention (CDC), the nation has witnessed sustained elevated activity across multiple key indicators in many areas, signaling the definitive start of the current flu season. The timing of this increasing activity mirrors several past seasons, yet the intensity and distribution patterns reveal unique characteristics that demand attention from healthcare providers, public health officials, and the general public.

The influenza A(H3N2) viruses have dominated the current season, accounting for the vast majority of reported cases nationwide. Among 216 influenza A(H3N2) viruses that underwent additional genetic characterization at the CDC since September 28, 2025, an alarming 89.8% belonged to subclade K – a notable mutation that has raised concerns among epidemiologists and infectious disease specialists. This particular variant, known for causing more intense symptoms including fever, chills, headache, fatigue, cough, sore throat, and runny nose, has been detected as the primary culprit in rising global cases. The CDC has preliminarily estimated that at least 4.6 million illnesses, 49,000 hospitalizations, and 1,900 deaths have occurred from influenza so far this season, underscoring the severity and widespread impact of the virus across American communities.

Latest Influenza Facts and Statistics in the US 2025

Data Source: CDC FluView Weekly Influenza Surveillance Report Week 50 (Ending December 13, 2025), CDC Respiratory Virus Activity Dashboard, CDC FluSurv-NET Hospitalization Surveillance

The statistics presented in the table above reveal the comprehensive scope of the 2025 influenza outbreak across the United States. The cumulative hospitalization rate of 11 per 100,000 population observed during Week 50 represents the third highest cumulative rate at this point in the season since the 2010-2011 flu season, following only the 2022-2023 season with a rate of 42.4 and the 2023-2024 season with a rate of 13.6. This elevated hospitalization metric signals that the current season has progressed beyond typical seasonal patterns and warrants heightened vigilance from the medical community.

The national test positivity rate of 14.8% during Week 50 demonstrates significant viral circulation, with clinical laboratories across the nation processing 70,675 specimens during that week alone, of which 10,456 tested positive for influenza. The emergence of the H3N2 subclade K variant, which accounts for nearly 90% of characterized H3N2 viruses, has introduced a more aggressive form of influenza that has resulted in more severe symptoms compared to previous variants. The World Health Organization has stated that this K variant marks a notable evolution in influenza A (H3N2) viruses, raising questions about the effectiveness of this season’s influenza vaccine against the strain.

Respiratory Illness Activity Levels by State in the US 2025

Data Source: CDC Respiratory Virus Activity Levels Dashboard, CDC FluView Weekly Surveillance Report for Week 50 Ending December 13, 2025, CDC National Syndromic Surveillance Program (NSSP)

The respiratory illness activity data demonstrates concentrated pockets of very high influenza transmission across the United States, with the Northeast corridor experiencing the most severe impact. New York City has reported the highest classification at Very High Level 1, indicating unprecedented demand for medical services related to respiratory illness. The state of New York follows closely with Very High Level 2 classification, while New Jersey and Rhode Island both show Very High Level 3 activity, creating a regional hotspot that encompasses one of the nation’s most densely populated areas.

The geographic distribution extends beyond the Northeast, with Louisiana and Colorado also reporting Very High Level 3 activity levels. This pattern suggests that the current flu season is not confined to a single region but has established multiple transmission centers across diverse climate zones and population densities. The High activity designations for states including Massachusetts, Connecticut, Michigan, Idaho, and South Carolina indicate that respiratory illness is spreading rapidly throughout these jurisdictions, with emergency department visits increasing substantially compared to baseline levels.

Influenza Hospitalization Rates by Age Group in the US 2025

Data Source: CDC Influenza Hospitalization Surveillance Network (FluSurv-NET) Week 50 Data (December 13, 2025), CDC FluView Hospitalization Surveillance

The age-stratified hospitalization data reveals stark disparities in influenza severity across different demographic groups during the 2025-2026 flu season. Adults aged 65 years and older face the highest burden, with a cumulative hospitalization rate of 31.4 per 100,000 population – nearly three times higher than the overall population rate. This vulnerable population also shows the highest weekly admission rate at 8.5 per 100,000, demonstrating ongoing acute transmission within senior communities and healthcare facilities.

Young children aged 0-4 years represent the second-most impacted age group with a cumulative rate of 14.4 per 100,000 and a weekly rate of 3.7 per 100,000. The substantial hospitalization burden among infants and toddlers raises concerns about daycare transmission, limited prior immunity, and the physiological vulnerabilities inherent to this age group. The 412 total hospitalizations among this young cohort during the surveillance period underscore the importance of vaccination for eligible children and their close contacts to provide protective immunity during this critical developmental stage.

Adults aged 50-64 years show moderate but significant hospitalization rates at 9.9 per 100,000 cumulatively and 2.4 per 100,000 weekly, with 668 total hospitalizations reported. This age group often experiences complications due to underlying chronic conditions such as diabetes, heart disease, and respiratory disorders, which compound the severity of influenza infection. The relatively high rates in this demographic emphasize that influenza poses serious health risks well before reaching senior citizen status.

Influenza Virus Characterization and Dominant Strains in the US 2025

Data Source: CDC Influenza Virus Characterization Report Week 50 (2025-2026 Season), CDC Genetic and Antigenic Characterization Data from September 28, 2025 through December 13, 2025

The virologic surveillance data confirms that influenza A viruses overwhelmingly dominate the 2025-2026 season, accounting for 94% of all positive specimens tested since the season began. Within the influenza A category, the H3N2 subtype has emerged as the predominant strain, representing 81.5% of subtyped influenza A viruses. The genetic characterization reveals that subclade K accounts for 89.8% of all H3N2 viruses that underwent detailed analysis, establishing it as the definitive variant driving this season’s outbreak.

The antigenic characterization results raise significant concerns regarding vaccine effectiveness. Among 35 A(H3N2) viruses tested for antigenic properties, only 3 viruses (9%) were well-recognized by ferret antisera to the vaccine reference virus. This low recognition rate suggests that the subclade K variant has undergone antigenic drift sufficient to partially evade vaccine-induced immunity. However, partial protection still provides meaningful benefits by reducing disease severity, hospitalization risk, and transmission potential.

In contrast, the influenza A(H1N1)pdm09 viruses show excellent vaccine match characteristics. All 23 H1N1pdm09 viruses (100%) tested demonstrated strong antigenic recognition by vaccine antisera, indicating that the vaccine component targeting this subtype should provide robust protection. The influenza B/Victoria lineage viruses showed moderate vaccine compatibility, with 8 of 12 tested viruses (67%) well-recognized by vaccine antisera.

Regional Influenza Test Positivity Rates in the US 2025

Data Source: CDC FluView Regional Surveillance Data Week 50 (December 13, 2025), CDC Clinical Laboratory Test Results by HHS Region

The regional test positivity analysis reveals dramatic geographic variation in influenza transmission intensity across the United States during the 2025-2026 season. HHS Region 8, encompassing the Mountain states of Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming, recorded the nation’s highest test positivity rate at 27.2% during Week 50. This means that more than one in four respiratory specimens tested in this region returned positive for influenza virus, indicating widespread community transmission and substantial disease burden.

The elevated rates in Region 8 correlate with the Very High activity classification for Colorado, which has experienced intensive influenza circulation throughout December 2025. The geographic characteristics of this region, including high altitude, cold winter temperatures, and concentrated indoor activity during harsh weather, likely contribute to enhanced viral transmission. Healthcare facilities across the region have reported increased emergency department visits and hospital admissions related to influenza-like illness.

Region 10, comprising Alaska, Idaho, Oregon, and Washington, demonstrated the lowest regional test positivity rate at 6.4% during Week 50, though this decreased rate may reflect limited data reporting during the holiday period rather than genuine improvement in disease activity. All other HHS regions showed increasing test positivity rates, with Regions 1, 2, 3, 4, 5, 6, 7, and 9 experiencing upward trends compared to the previous week.

Influenza-Like Illness (ILI) Activity by Jurisdiction in the US 2025

Data Source: CDC ILINet Outpatient Illness Surveillance Week 50 (December 13, 2025), CDC State and CBSA Activity Level Classifications

The Influenza-Like Illness surveillance network (ILINet) data provides crucial insights into outpatient healthcare utilization patterns across the United States during the 2025 flu season. During Week 50, 4.1% of patient visits reported through ILINet were attributed to respiratory illness presenting with fever plus cough or sore throat. This national percentage exceeded the baseline threshold of 3.1% for the second consecutive week, confirming sustained community transmission of respiratory pathogens including influenza, COVID-19, and RSV.

The distribution of activity levels reveals that 6 states or jurisdictions have reached Very High ILI activity, with New York City leading this classification. An additional 11 jurisdictions reported High activity levels, including major population centers such as Massachusetts, Connecticut, Washington D.C., Maryland, North Carolina, and Georgia. Combined, these 17 high-burden jurisdictions encompass millions of Americans experiencing increased respiratory illness requiring medical attention.

The geographic spread is evident in the Core Based Statistical Areas (CBSAs) data, with 17 CBSAs classified as Very High and 62 CBSAs as High activity. These metropolitan and micropolitan statistical areas represent concentrated population centers where person-to-person transmission occurs more readily due to higher population density, frequent social interactions, and shared indoor spaces during winter months.

Influenza Hospitalizations by Race and Ethnicity in the US 2025

Data Source: CDC FluSurv-NET Race and Ethnicity Hospitalization Data Week 50 (December 13, 2025), Age-Adjusted Rates by Demographic Group

The racial and ethnic disparities in influenza hospitalization rates during the 2025-2026 season reflect longstanding health inequities that persist in American healthcare. Non-Hispanic Black persons experience the highest age-adjusted hospitalization rate at 21.1 per 100,000 population – nearly double the overall population rate of 11.0 per 100,000. This pronounced disparity likely stems from multiple factors including higher prevalence of underlying chronic conditions, socioeconomic barriers to preventive care, reduced vaccination rates, and systemic healthcare access challenges.

American Indian and Alaska Native persons face the second-highest burden with a rate of 13.4 per 100,000, representing 22% above the overall population rate. Indigenous communities have historically experienced disproportionate impacts from infectious diseases due to factors including geographic isolation, limited healthcare infrastructure in tribal areas, housing conditions conducive to disease transmission, and higher rates of comorbid conditions such as diabetes and respiratory disease.

Hispanic persons show hospitalization rates of 10.9 per 100,000, closely approximating the overall population average. However, this aggregate figure may mask significant variation among diverse Hispanic subpopulations, immigration statuses, and geographic regions. Non-Hispanic White persons and Asian/Pacific Islander persons demonstrate lower hospitalization rates at 8.7 and 5.1 per 100,000 respectively, though these populations still experience substantial influenza burden in absolute numbers.

Emergency Department Visits for Influenza in the US 2025

Data Source: CDC National Syndromic Surveillance Program (NSSP) Week 50 Data, CDC National Healthcare Safety Network (NHSN) Hospital Respiratory Data December 13, 2025

The emergency department surveillance data from the National Syndromic Surveillance Program reveals that 2.8% of all ED visits nationally during Week 50 carried a discharge diagnosis of influenza. This percentage increased compared to the previous week across all ten HHS regions and among all age groups, signaling accelerating disease transmission. The comprehensive geographic spread indicates that influenza has established sustained community circulation throughout the United States rather than remaining confined to isolated outbreak clusters.

The age-stratified increases demonstrate that influenza is impacting Americans across the entire lifespan. Children aged 0-4 years and 5-17 years show rising ED utilization, likely reflecting school and daycare transmission dynamics along with parents’ heightened concern about pediatric respiratory illness. Working-age adults 18-64 years also exhibit increased ED visits, potentially causing significant workforce disruptions and economic impacts. Seniors aged 65 years and older experience disproportionate ED utilization due to higher complication rates and increased severity of illness.

The National Healthcare Safety Network (NHSN) hospital data shows that 9,944 laboratory-confirmed influenza patients were admitted to hospitals during Week 50, with a national admission rate of 2.9 per 100,000 population. This rate increased substantially (difference ≥0.2) compared to Week 49, confirming that hospitalization pressure continues intensifying across American healthcare systems.

Mortality and Pediatric Deaths from Influenza in the US 2025

Data Source: CDC National Center for Health Statistics (NCHS) Mortality Surveillance Week 50, CDC Influenza-Associated Pediatric Mortality Data December 2025

The mortality surveillance data reveals the tragic human cost of the 2025-2026 influenza season. Based on National Center for Health Statistics mortality surveillance data, 0.3% of all deaths occurring during Week 50 were attributed to influenza, representing an increase compared to the previous week. While this percentage may appear small, it translates to approximately 1,900 influenza-associated deaths nationwide since the season began in October 2025, with projections suggesting this number will continue rising as the season progresses through winter months.

The three pediatric deaths reported during the 2025-2026 season serve as devastating reminders that influenza poses life-threatening risks even to previously healthy children. Two deaths occurred during the recent surge in late November and mid-December, both associated with influenza A(H3N2) infection. An earlier pediatric death associated with influenza B/Victoria virus occurred during Week 22 in May 2025, technically falling within the current surveillance year. Each pediatric death undergoes detailed investigation to identify contributing factors, underlying conditions, and opportunities for prevention.

The context of the previous season’s 287 pediatric deaths during 2024-2025 emphasizes the substantial burden that influenza places on America’s children. That season was classified as high severity, marking the most severe influenza season since 2017-2018. While the current season’s pediatric death count remains low compared to the previous year, influenza activity is still increasing, and peak transmission has not yet occurred.

Long-Term Care Facility Influenza Impact in the US 2025

Data Source: CDC National Healthcare Safety Network (NHSN) Long-Term Care Respiratory Pathogens & Vaccination Module Week 50 Data, December 13, 2025

Long-term care facilities, including nursing homes and skilled nursing facilities, represent particularly vulnerable environments during influenza outbreaks. During Week 50, the hospitalization rate for residents who tested positive for influenza within the previous 10 days reached 14.3 per 100,000 residents nationally. This elevated rate has shown consistent increases over the past several weeks across nine of the ten HHS regions, indicating widespread transmission within congregate care settings where elderly individuals with multiple chronic conditions reside in close quarters.

The increasing trend in Regions 1 through 9 reflects the challenges of controlling respiratory virus transmission in institutional settings despite infection control measures. Residents of long-term care facilities typically have compromised immune systems, multiple underlying health conditions, and limited mobility, all factors that increase susceptibility to severe influenza complications. Additionally, the congregate nature of these facilities, with shared dining areas, common spaces, and frequent staff-resident interactions, facilitates rapid viral spread once introduced.

Region 10 demonstrates a low rate without consistent trending patterns, potentially reflecting different facility characteristics, more aggressive infection control protocols, or varying reporting practices. However, given the overall national pattern, facilities in this region should maintain heightened vigilance and robust prevention strategies to avoid following the trajectory observed in other regions.

Influenza Vaccination Coverage in the US 2025

Data Source: CDC Weekly Flu Vaccination Dashboard December 2025, CDC FluVaxView Vaccination Coverage Data, CDC FluView Week 50 Surveillance Report

The influenza vaccination coverage data for the 2025-2026 season reveals concerning gaps in preventive care uptake across the American population. While 130 million vaccine doses have been distributed as of early December 2025, administration rates lag behind the previous season. Retail pharmacies have administered approximately 2.1 million fewer doses compared to the same timepoint during the 2024-2025 season, while physician offices show a decrease of nearly 873,000 doses. These shortfalls suggest reduced vaccination enthusiasm or potential access barriers among Americans despite widespread availability.

The age-stratified coverage estimates from the previous season provide context for current challenges. Adults aged 18-49 years achieved only 35% vaccination coverage during 2024-2025, leaving nearly two-thirds of working-age Americans unprotected against influenza. This low uptake among younger and middle-aged adults contributes to ongoing transmission and workforce disruptions. In contrast, seniors aged 65 years and older demonstrated much higher coverage at 71%, though even this leaves nearly 30% of the most vulnerable age group susceptible to severe complications.

Perhaps most troubling is that among hospitalized patients during the previous season, only 32.4% had been vaccinated, suggesting that vaccination could have prevented substantial morbidity and healthcare system burden. The 2025-2026 vaccines are trivalent formulations designed to protect against H1N1, H3N2, and influenza B viruses, with manufacturers projecting sufficient supply to vaccinate the entire eligible population if uptake improves.

Antiviral Treatment and Resistance Patterns in the US 2025

Data Source: CDC Influenza Virus Antiviral Susceptibility Testing Data September 28, 2025 through December 13, 2025, CDC FluView Week 50 Antiviral Surveillance

The antiviral susceptibility testing conducted on influenza viruses circulating during the 2025-2026 season provides reassuring evidence that currently available treatment options remain effective. The CDC tested 354 influenza viruses for susceptibility to the three neuraminidase inhibitor antivirals – oseltamivir (Tamiflu), peramivir, and zanamivir – and found zero instances of reduced or highly reduced susceptibility. This means that all tested viruses remain fully susceptible to these frontline antiviral medications, which are most effective when initiated within 48 hours of symptom onset.

Additionally, 341 viruses underwent testing for susceptibility to baloxavir marboxil, the newer PA endonuclease inhibitor antiviral medication, with zero viruses showing decreased susceptibility. This comprehensive antiviral surveillance ensures that clinicians can confidently prescribe these medications to high-risk patients, hospitalized individuals, and those with severe illness, knowing that treatment effectiveness is not compromised by resistance mechanisms.

However, the adamantane class antivirals (amantadine and rimantadine) remain unsuitable for treatment due to persistently high resistance rates among influenza A(H1N1)pdm09 and H3N2 viruses. These medications have not been recommended for influenza treatment in the United States for over a decade, and resistance testing is no longer routinely performed. The CDC emphasizes that neuraminidase inhibitors and baloxavir represent the only viable antiviral treatment options for the current season.

State-Level Outpatient Respiratory Illness in the US 2025

Data Source: CDC ILINet State Activity Level Classifications Week 50 (December 13, 2025), CDC Respiratory Virus Activity Dashboard State Maps

The state-level outpatient respiratory illness activity data documents the rapid escalation of influenza-like illness across multiple states during Week 50 of 2025. Rhode Island and Colorado both experienced dramatic increases of 2 activity levels in a single week, vaulting from High to Very High classifications. Such rapid progression indicates explosive community transmission that has overwhelmed typical seasonal patterns and challenged healthcare capacity in these states.

Maryland similarly jumped 2 levels from Moderate to High Level 3, while New York, Louisiana, Massachusetts, Michigan, Washington D.C., North Carolina, and Georgia each increased 1 activity level. This widespread simultaneous escalation across geographically diverse states spanning the Northeast, South, Midwest, and Mountain regions demonstrates that the 2025-2026 influenza season has established nationwide transmission rather than progressing through predictable regional waves.

States classified as Very High – New York, New Jersey, Rhode Island, Louisiana, and Colorado – are experiencing unprecedented burdens on their healthcare systems. Primary care providers, urgent care centers, and emergency departments in these states report increased wait times, bed shortages, and staff absences due to influenza infection. Public health authorities have issued advisories urging residents to seek vaccination if not yet protected, practice respiratory hygiene, and consider staying home when ill to reduce transmission.

Clinical Presentation and Severity Indicators in the US 2025

Data Source: CDC FluView Clinical Severity Indicators, CDC Antigenic Characterization Reports, Expert Clinical Assessment of H3N2 Subclade K Variant

The clinical presentation of influenza during the 2025-2026 season, particularly cases caused by the H3N2 subclade K variant, has been characterized by more intense and prolonged symptoms compared to recent seasons. Healthcare providers across the nation report that patients are presenting with high fevers often exceeding 102°F (39°C), severe body aches and fatigue that impair daily functioning, and respiratory symptoms including persistent cough and sore throat. The symptom intensity has resulted in higher rates of healthcare-seeking behavior and increased antibiotic prescriptions for presumed secondary bacterial infections.

The subclade K variant’s more aggressive nature stems from antigenic changes that may enhance viral replication efficiency or immune evasion capabilities. While the vaccine match of only 9% for this variant raises concerns, epidemiological studies from previous seasons demonstrate that even partially matched vaccines provide meaningful protection against severe outcomes including hospitalization and death. Vaccinated individuals who contract influenza typically experience milder illness, shorter symptom duration, and reduced complication rates.

Secondary bacterial infections, particularly pneumonia caused by Streptococcus pneumoniae and Staphylococcus aureus, represent significant contributors to influenza-related morbidity and mortality. The initial viral infection damages respiratory epithelium, creating opportunities for bacterial colonization and invasion. Patients who experience improvement followed by sudden clinical deterioration should be evaluated for bacterial superinfection requiring antibiotic therapy in addition to antiviral treatment.

HHS Regional Distribution and Transmission Patterns in the US 2025

Data Source: CDC FluView Regional Surveillance Week 50 (December 13, 2025), HHS Regional Office Designations, CDC Clinical Laboratory Regional Test Positivity Rates

The Health and Human Services regional analysis reveals that nine of ten regions experienced increasing influenza test positivity during Week 50, demonstrating synchronized national transmission. Region 8’s record-breaking 27.2% positivity rate stands out as the most alarming regional metric, suggesting that more than one in four patients tested for influenza in Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming return positive results. This Mountain region’s cold winter temperatures, high elevation, and tendency toward indoor congregation during harsh weather likely amplify viral transmission.

Region 2, encompassing New York and New Jersey, demonstrates the second-highest activity levels nationally, with both states classified as Very High. The region’s dense urban population, extensive public transportation networks, and high-rise apartment buildings create ideal conditions for respiratory virus spread. New York City specifically has been designated as Very High Level 1, the most severe classification possible, indicating overwhelming healthcare system demand and widespread community transmission.

Regions 1, 3, 4, 5, 6, and 7 all show concerning increases, though none match the intensity observed in Regions 2 and 8. These regions contain major metropolitan areas including Boston, Philadelphia, Atlanta, Chicago, Houston, and Kansas City, where millions of Americans live and work in close proximity. The simultaneous escalation across these diverse geographic areas suggests that the 2025-2026 season will affect virtually all Americans regardless of location.

Region 10 presents the only notable exception with a 6.4% positivity rate and slight decrease compared to the previous week. However, surveillance experts caution that this apparent improvement may reflect incomplete data reporting during the late December holiday period rather than genuine disease reduction. Alaska, Idaho, Oregon, and Washington should remain vigilant as the season progresses into January and February, traditionally peak months for influenza activity.

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.

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