National Influenza Activity: - According to this week’s FluView report, seasonal influenza activity remains elevated nationally, but trends in activity vary across age groups and regions.
- CDC is providing updated information and materials on the current HPAI A(H5N1) situation. The webpage can be viewed here.
Influenza Activity in the U.S. Key Points: - Seasonal influenza activity remains elevated nationally, but has decreased for three consecutive weeks. Of note, among school-aged children, emergency department visits for influenza are increasing and hospitalizations remain stable this week.
- CDC's in-seasonseverity assessment framework classified the season as moderate across all ages. CDC also assesses severity by three age groups: pediatric (0-17 years), adult (18-64 years), and older adults (≥65 years). At this point in the season, the pediatric age group is classified as having high severity, while both the adult and older adult age groups are classified as having moderate severity. These assessments are conducted each week during the season, and the season's severity assessment can change if activity should increase again.
- Among 659 influenza A(H3N2) viruses collected since September 28, 2025, that underwent additional genetic characterization at CDC, 90.4% belonged to subclade K.
- Twelve influenza-associated pediatric deaths occurring in the 2025-2026 season were reported to CDC this week, bringing the season total to 44 reported influenza-related pediatric deaths.
- Among children who were eligible for influenza vaccination and with known vaccine status, approximately 90% of reported pediatric deaths this season have occurred in children who were not fully vaccinated against influenza.
- CDCestimatesthat there have been at least 19,000,000 illnesses, 250,000 hospitalizations, and 10,000 deaths from flu so far this season.
- Influenza vaccination has been shown to reduce the risk of flu and its potentially serious complications. There is still time to get vaccinated against flu this season. MDPH recommends that everyone 6 months and older who has not yet been vaccinated this season get an annual influenza (flu) vaccine. Approximately 130 million doses of influenza vaccine have been distributed in the United States this season.
- There areprescription flu antiviral drugs that can treat flu illness; those should be started as early as possible and are especially important for patients at higher risk for flu-related complications.
- Influenza viruses are among several viruses contributing to respiratory disease activity. CDC provides updated, integrated information about COVID-19, flu, and respiratory syncytial virus (RSV) activity on a weekly basis.
- No new avian influenza A(H5) infections were reported to CDC this week. To date, person-to-person transmission of influenza A(H5) viruses has not been identified in the United States.
Below is a summary of the key influenza indicators for the week ending January 17, 2026:
Viral Surveillance - Clinical Lab: The percentage of respiratory specimens testing positive for influenza at clinical laboratories is 17.7% this week.
Viral Surveillance - Public Health Lab: The most frequently reported influenza viruses this week were influenza A(H3N2).
Virus Characterization: Influenza virus characterization information can be found here: U.S. Influenza Surveillance: Purpose and Methods | CDC
Outpatient Illness: The percentage of patient visits to a health care provider for respiratory illness in Week 2 was 4.4%, which is above baseline.
Outpatient Respiratory Illness: ILINet Activity Map: Eleven jurisdictions experienced moderate ILI activity and 31 jurisdictions experienced high or very high ILI activity in Week 2.
Laboratory-Confirmed influenza Hospitalizations can be found here: Laboratory-Confirmed Influenza Hospitalizations (cdc.gov) The weekly hospitalization rate observed in Week 2 was 2.9 per 100,000 population. The cumulative hospitalization rate was 55.4 per 100,000 population.
NCHS Mortality: 1.8% of deaths were due to influenza this week. This percentage decreased (≥0.1 percentage point change) compared to Week 1. (NCHS: National Center for Health Statistics)
Influenza-Associated Pediatric Deaths: Twelve influenza-associated deaths were reported this week. Forty-four pediatric deaths have been reported so far this season. For more information: https://gis.cdc.gov/GRASP/Fluview/PedFluDeath.html
CDC FluView Site
https://www.cdc.gov/fluview/
Influenza Activity in Massachusetts
For more information about flu, please go to our Viral Respiratory Disease Dashboard which includes information not only on influenza but also other acute respiratory diseases, COVID-19, and respiratory syncytial virus (RSV), wastewater data and immunizations for respiratory diseases.
The figure below shows that for MMWR week 2, the percent of ILI visits in the current week is above the regional baseline of 2.2%. (The CDC uses trends from past years to determine a region-specific baseline rate of ILI visits, which for Massachusetts is 2.2%. A rate above this regional baseline indicates higher than normal levels of ILI in the state.) For more information on how regional baselines are calculated see CDC’s influenza surveillance website at U.S. Influenza Surveillance: Purpose and Methods | FluView | CDC) For more information on weekly flu activity, see CDC’s influenza surveillance website at https://www.cdc.gov/fluview/surveillance/index.html.
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ILI Activity in Massachusetts by Region
The map below shows the relative intensity of reported ILI activity in Massachusetts by region. Although regions may not all experience the same intensity of ILI at similar times, infections due to influenza can be found throughout Massachusetts during flu season. At this time, the Northeast, Outer Metro Boston and Southeast regions are experiencing very high ILI activity. The West, Central, Inner Metro Boston and Boston regions are experiencing high ILI activity.
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Influenza Vaccination in Massachusetts
Approximately 1 out of every 3 Massachusetts residents have been vaccinated against influenza this season.
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