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Influenza (Flu)
Influenza (Flu) Home
 1. Seasonal Flu
 2. Flu Activity & Surveillance




WEEKLY U.S. INFLUENZA SURVEILLANCE REPORT

Print
Weekly U.S. Influenza Surveillance Report (FluView)

Updated March 10, 2023

minus
Related Pages


Note: CDC is also tracking the impact of other respiratory viruses,
including COVID-19.  Data comparing the impact of these viruses can be found in
two new dashboards: RESP-NET and NSSP’s Emergency Department Visits for
COVID-19, Influenza and Respiratory Syncytial Virus.

Key Updates for Week 9, ending March 4, 2023

Seasonal influenza activity remains low nationally.




VIRUSES

Clinical Lab


0.9%

(TREND )

positive for influenza
this week

Public Health Lab

The most frequently reported viruses this week were influenza A(H3N2).

Virus Characterization

Genetic and antigenic characterization and antiviral susceptibility are
summarized in this report.


ILLNESS

Outpatient Respiratory Illness


2.4%

(TREND )

of visits to a health care provider this week were for respiratory illness
(below baseline).

Outpatient Respiratory Illness: Activity Map

This week 4 jurisdictions experienced moderate activity and 3 jurisdictions
experienced high activity.

Geographic Spread

Because of the ongoing COVID-19 pandemic, this system will suspend data
collection for the 2020-21 influenza season.

Long-term Care Facilities


0.5%

(TREND )

of facilities reported
≥ 1 influenza-positive test
among residents this week.

FluSurv-NET


60.0 PER 100,000

cumulative hospitalization rate

HHS Protect Hospitalizations


1,418 

(TREND )

patients admitted to hospitals with influenza
this week.

NCHS Mortality


8.9%

(TREND )

of deaths attributed to pneumonia, influenza, or COVID-19 this week (above
threshold).

Pediatric Deaths


8

deaths were reported this week for a total of
125 so far this season

All data are preliminary and may change as more reports are received.

Directional arrows indicate changes between the current week and the previous
week. Additional information on the arrows can be found at the bottom of this
page.

A description of the CDC influenza surveillance system, including methodology
and detailed descriptions of each data component is available on the
surveillance methods page.

Additional information on the current and previous influenza seasons for each
surveillance component are available on FluView Interactive.

Key Points

 * Seasonal influenza activity remains low nationally.
 * Nationally, outpatient respiratory illness is now below baseline, and eight
   of 10 HHS regions are below their respective baselines.
 * The number and weekly rate of flu hospital admissions decreased compared to
   week 8.
   * Hospitals reported 1,418 influenza hospitalizations to HHS Protect during
     week 9 compared to 1,644 reported during week 8.
   * The weekly rate of flu hospital admissions in the FluSurv-NET declined
     again during week 9.
 * Of the 51 influenza A viruses detected and subtyped during week 9, 55% were
   influenza A(H3N2) and 45% were influenza A(H1N1).
 * Eight influenza-associated pediatric deaths that occurred during the
   2022-2023 season were reported this week, for a total of 125 pediatric flu
   deaths reported so far this season.
 * CDC estimates that, so far this season, there have been at least 26 million
   illnesses, 290,000 hospitalizations, and 18,000 deaths from flu.
 * The majority of influenza viruses tested are in the same genetic subclade as
   and antigenically similar to the influenza viruses included in this season’s
   influenza vaccine.
 * Recommendations for U.S. flu vaccine composition for the 2023-2024 season
   have been made and include an update to the influenza A(H1N1)pdm09 component.
 * All viruses collected and evaluated this season have been susceptible to the
   influenza antivirals peramivir, zanamivir, and baloxavir, and all viruses
   except for one (> 99.9%) have been susceptible to the influenza antiviral
   oseltamivir.
 * CDC continues to recommend that everyone ages 6 months and older get an
   annual flu vaccine as long as flu activity continues.
 * There are also prescription flu antiviral drugs that can be used to treat flu
   illness; those need to be started as early as possible.


U.S. VIROLOGIC SURVEILLANCE

Nationally, the percentage of specimens testing positive for influenza in
clinical laboratories remained stable (change of <0.5 percentage points). For
regional and state level data and age group distribution, please visit FluView
Interactive. Viruses known to be associated with recent live attenuated
influenza vaccine (LAIV) receipt or found upon further testing to be a vaccine
virus are not included, as they are not circulating influenza viruses.


CLINICAL LABORATORIES

The results of tests performed by clinical laboratories nationwide are
summarized below. Data from clinical laboratories (the percentage of specimens
tested that are positive for influenza) are used to monitor whether influenza
activity is increasing or decreasing.

 

results of tests from Clinical Laboratories Week 9
Data Cumulative since October 2, 2022(Week 40)
No. of specimens tested 64,083 2,609,725 No. of positive specimens (%) 565
(0.9%) 335,167 (12.8%) Positive specimens by type Influenza A 396 (70.1%)
331,473 (98.9%) Influenza B 169 (29.9%) 3,694 (1.1%)

View Chart Data | View Full Screen


PUBLIC HEALTH LABORATORIES

The results of tests performed by public health laboratories nationwide are
summarized below.  Data from public health laboratories are used to monitor the
proportion of circulating viruses that belong to each influenza subtype/lineage.

results of tests from Public Health Laboratories Week 9 Data Cumulative since
October 2, 2022
(Week 40)
No. of specimens tested 6,414 195,177 No. of positive specimens 88 27,866
Positive specimens by type/subtype              Influenza A 72 (81.8%) 27,630
(99.2%)             (H1N1)pdm09 23 (45.1%) 5,880 (25.6%)              H3N2 28
(54.9%) 17,127 (74.4%)              H3N2v 0 1 (<0.1%)              Subtyping not
performed 21 4,622         Influenza B 16 (18.2%) 236 (0.8%)           
 Yamagata lineage 0 0             Victoria lineage 7 (100%) 178 (100%)         
   Lineage not performed 9 58



 


View Chart Data | View Full Screen

--------------------------------------------------------------------------------

Additional virologic surveillance information for current and past seasons:
Surveillance Methods | FluView Interactive: National, Regional, and State Data
or Age Data




INFLUENZA VIRUS CHARACTERIZATION

CDC performs genetic and antigenic characterization of U.S. viruses submitted
from state and local public health laboratories according to the Right Size
Roadmap submission guidance. These data are used to compare how similar the
currently circulating influenza viruses are to the reference viruses
representing viruses contained in the current influenza vaccines. The data are
also used to monitor evolutionary changes that continually occur in influenza
viruses circulating in humans.

CDC genetically characterized 2,320 influenza viruses collected since October 2,
2022. To reflect the genetic diversity of the HA genes in recent A(H1N1)pdm09
and A(H3N2) viruses, new subclades have been designated. The vast majority of
A(H1N1)pdm09 viruses collected in the U.S. this season express HA genes
belonging to 6B.1A.5a.2 but this clade has been split into the 2a and 2a.1
subclades. All A(H3N2) viruses collected thus far in the U.S. this season
express HA genes belonging to clade 3C.2a1b.2a.2 and this clade has been split
into multiple subclades. The new subclade designations improve the ability to
track the evolution and co-circulation of multiple groups of influenza viruses.

Influenza Virus Characterization from viruses collected in the U.S. from
September 29, 2019 Virus Subtype or Lineage Genetic Characterization Total No.
of
Subtype/Lineage
Tested HA
Clade Number (% of
subtype/lineage
tested) HA
Subclade Number (% of
subtype/lineage
tested) A/H1 829 6B.1A.5a 829 (100%) 1 5 (0.6%) 2a 129 (15.6%) 2a.1 695 (83.8%)
A/H3 1,427 3C.2a1b.2a 1,427 (100%) 2a 25 (1.8%) 2a.1 164 (11.5%) 2a.1b 102
(7.1%) 2a.2c 0 (0%) 2a.3 41 (2.9%)   2a.3a 3 (0.2%) 2a.3a.1 43 (3.0%) 2a.3b 8
(0.6%) 2b 1,041 (73.0%) B/Victoria 64 V1A 64 (100%) 3 4 (6.3%) 3a.2 60 (93.8%)
B/Yamagata 0 Y3 0 Y3 0 (0%)

 

CDC antigenically characterizes influenza viruses by hemagglutination inhibition
(HI) (H1N1pdm09, B/Victoria and B/Yamagata viruses) or neutralization-based HINT
(H3N2 viruses) using antisera that ferrets make after being infected with
reference viruses representing the 2022-2023 Northern Hemisphere recommended
cell or recombinant-based vaccine viruses. Antigenic differences between viruses
are determined by comparing how well the antibodies made against the vaccine
reference viruses recognize the circulating viruses that have been grown in cell
culture. Ferret antisera are useful because antibodies raised against a
particular virus can often recognize small changes in the surface proteins of
other viruses. In HI assays, viruses with similar antigenic properties have
antibody titer differences of less than or equal to 4-fold when compared to the
reference (vaccine) virus. In HINT, viruses with similar antigenic properties
have antibody neutralization titer differences of less than 8-fold. Viruses
selected for antigenic characterization are a subset representing the genetic
changes in the surface proteins seen in genetically characterized viruses.

Influenza A Viruses

 * A (H1N1)pdm09: Eighty-five A(H1N1)pdm09 viruses were antigenically
   characterized by HI, and 84 (99.9%) were well-recognized (reacting at titers
   that were within 4-fold of the homologous virus titer) by ferret antisera to
   cell-grown A/Wisconsin/588/2019-like reference viruses representing the
   A(H1N1)pdm09 component for the cell- and recombinant- based influenza
   vaccines.
 * A (H3N2): One hundred and seventy-nine A(H3N2) viruses were antigenically
   characterized by HINT, and 167 (93%) were well-recognized (reacting at titers
   that were within 8-fold of the homologous virus titer) by ferret antisera to
   cell-grown A/Darwin/6/2021-like reference viruses representing the A(H3N2)
   component for the cell- and recombinant-based influenza vaccines.

Influenza B Viruses

 * B/Victoria: Thirteen influenza B/Victoria-lineage virus were antigenically
   characterized by HI, and thirteen (100%) were well-recognized (reacting at
   titers that were within 4-fold of the homologous virus titer) by ferret
   antisera to cell-grown B/Austria/1359417/2021-like reference viruses
   representing the B/Victoria component for the cell- and recombinant-based
   influenza vaccines.
 * B/Yamagata: No influenza B/Yamagata-lineage viruses were available for
   antigenic characterization.

 





2023-2024 Influenza Season – U.S. Influenza Vaccine Composition:

The World Health Organization (WHO) has recommended the Northern Hemisphere
2023-2024 influenza vaccine composition, and the Food and Drug Administration’s
Vaccines and Related Biological Products Advisory Committee (VRBPAC)
subsequently made the influenza vaccine composition recommendation for the
United States. Both agencies recommend that influenza vaccines contain the
following:

Egg-based vaccines

 * an A/Victoria/4897/2022 (H1N1)pdm09-like virus
 * an A/Darwin/9/2021 (H3N2)-like virus
 * a B/Austria/1359417/2021 (B/Victoria lineage)-like virus
 * a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus

Cell- or recombinant-based vaccines

 * an A/Wisconsin/67/2022 (H1N1)pdm09-like virus
 * an A/Darwin/6/2021 (H3N2)-like virus
 * a B/Austria/1359417/2021 (B/Victoria lineage)-like virus
 * a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus

The A(H1N1)pdm09 recommendation represents an update to the 2022-2023 Northern
Hemisphere vaccines. These vaccine recommendations were based on several
factors, including global influenza virologic and epidemiologic surveillance,
genetic characterization, antigenic characterization, and the candidate vaccine
viruses that are available for production.





Assessment of Virus Susceptibility to Antiviral Medications

CDC assesses susceptibility of influenza viruses to antiviral medications
including the neuraminidase inhibitors (oseltamivir, zanamivir, and peramivir)
and the PA endonuclease inhibitor baloxavir using next generation sequence
analysis supplemented by laboratory assays. Information about antiviral
susceptibility test methods can be found at U.S. Influenza Surveillance: Purpose
and Methods | CDC.

Viruses collected in the U.S. since October 2, 2022, were tested for antiviral
susceptibility as follows:

susceptibility of influenza viruses to the antiviral medications Antiviral
Medication Total
Viruses  A/H1   A/H3  B/Victoria B/Yamagata Neuraminidase
Inhibitors Oseltamivir Viruses
Tested 2,380 854 1,458 68 0 Reduced
Inhibition 1 (<0.1%) 1 (0.1%) 0 (0%) 0 (0%) 0 (0%) Highly
Reduced
Inhibition 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) Peramivir Viruses
Tested 2,380 854 1,458 68 0 Reduced
Inhibition 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) Highly
Reduced
Inhibition 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) Zanamivir Viruses
Tested 2,380 854 1,458 68 0 Reduced
Inhibition 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) Highly
Reduced
Inhibition 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) PA Cap-Dependent Endonuclease
Inhibitor Baloxavir Viruses
Tested 2,303 811 1,424 68 0 Reduced
Susceptibility 0 (0%) 0 (0%) 0 (0%) 0 (0%) 0 (0%)

One A(H1N1)pdm09 virus had NA-S247G amino acid substitution and showed reduced
inhibition by oseltamivir.




OUTPATIENT RESPIRATORY ILLNESS SURVEILLANCE

The U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet)
monitors outpatient visits for respiratory illness referred to as influenza-like
illness [ILI (fever plus cough or sore throat)], not laboratory-confirmed
influenza, and will therefore capture respiratory illness visits due to
infection with any pathogen that can present with similar symptoms, including
influenza, SARS-CoV-2, and RSV. Due to the COVID-19 pandemic, health
care-seeking behaviors have changed, and people may be accessing the health care
system in alternative settings not captured as a part of ILINet or at a
different point in their illness than they might have before the pandemic.
Therefore, it is important to evaluate syndromic surveillance data, including
that from ILINet, in the context of other sources of surveillance data to obtain
a complete and accurate picture of influenza, SARS-CoV-2, and other respiratory
virus activity. CDC is tracking the COVID-19 pandemic in a weekly publication
called COVID Data Tracker Weekly Review. Information about other respiratory
virus activity can be found on CDC’s National Respiratory and Enteric Virus
Surveillance System (NREVSS) website.


OUTPATIENT RESPIRATORY ILLNESS VISITS

Nationwide during week 9, 2.4% of patient visits reported through ILINet were
due to respiratory illness that included fever plus a cough or sore throat, also
referred to as ILI. This has decreased compared to week 8 and is below the
national baseline of 2.5%. Eight of the 10 HHS regions are below their
respective baselines; regions 2 and 9 are above their respective baselines.
Multiple respiratory viruses are co-circulating, and the relative contribution
of influenza virus infection to ILI varies by location.

* Effective October 3, 2021 (week 40), the ILI definition (fever plus cough or
sore throat) no longer includes “without a known cause other than influenza.”

View Chart Data (current season only) | View Full Screen




OUTPATIENT RESPIRATORY ILLNESS VISITS BY AGE GROUP

More than 70% of ILINet participants provide both the number of patient visits
for respiratory illness and the total number of patient visits for the week
broken out by age group. Data from this subset of providers are used to
calculate the percentages of patient visits for respiratory illness by age
group.

The percentage of visits for respiratory illness reported in ILINet remained
stable (change of ≤ 0.1 percentage points) for four age groups (5-24 years,
25-49 years, 50-64 years, 65+ years) and decreased in the 0-4 years age group in
week 9 compared to week 8.

View Chart Data | View Full Screen




OUTPATIENT RESPIRATORY ILLNESS ACTIVITY MAP

Data collected in ILINet are used to produce a measure of ILI activity* by
state/jurisdiction and Core Based Statistical Areas (CBSA).

ILI Activity by State/Jurisdiction and Core Based Statistical Area Activity
Level Number of Jurisdictions Number of CBSAs Week 9

(Week ending
Mar. 4, 2023)

Week 8

(Week ending 
Feb. 25, 2023)

Week 9

(Week ending
Mar. 4, 2023)

Week 8

(Week ending
Feb. 25, 2023)

Very High 0 0 1 4 High 3 5 21 20 Moderate 4 1 34 36 Low 10 9 101 119 Minimal 38
40 534 513 Insufficient Data 0 0 238 237

 



*Data collected in ILINet may disproportionally represent certain populations
within a jurisdiction or CBSA, and therefore, may not accurately depict the full
picture of influenza activity for the entire jurisdiction or CBSA. Differences
in the data presented here by CDC and independently by some health departments
likely represent differing levels of data completeness with data presented by
the health department likely being the more complete.

--------------------------------------------------------------------------------

Additional information about medically attended visits for ILI for current and
past seasons:
Surveillance Methods | FluView Interactive: National, Regional, and State Data
or ILI Activity Map


LONG-TERM CARE FACILITY (LTCF) SURVEILLANCE

LTCFs (e.g., nursing homes/skilled nursing, long-term care for the
developmentally disabled, and assisted living facilities) from all 50 states and
U.S. territories report data on influenza virus infections among residents
through the National Healthcare Safety Network (NHSN) Long-term Care Facility
Component. During week 9, 67 (0.5%) of 14,305 reporting facilities reported at
least one influenza positive test among their residents. This percentage remains
stable compared to week 8.


View Chart Data | View Full Screen

--------------------------------------------------------------------------------

Additional information about long-term care facility surveillance:
Surveillance Methods | Additional Data


HOSPITALIZATION SURVEILLANCE


FLUSURV-NET

The Influenza Hospitalization Surveillance Network (FluSurv-NET) conducts
population-based surveillance for laboratory-confirmed influenza-related
hospitalizations in select counties in 14 states and represents approximately 9%
of the U.S. population. FluSurv-NET hospitalization data are preliminary. As
data are received each week, prior case counts and rates are updated
accordingly.

A total of 17,565 laboratory-confirmed influenza-associated hospitalizations
were reported by FluSurv-NET sites between October 1, 2022, and March 4, 2023.
The weekly hospitalization rate observed in week 9 was 0.1 per 100,000
population. The weekly rate observed during week 48 (week ending December 3,
2022) is the third highest peak weekly rate observed during all seasons going
back to 2010-2011; this follows the 2017-2018 season, which peaked during week 1
(week ending January 6, 2018), and the 2014-2015 season which peaked during week
52 (week ending December 27, 2014).

The overall cumulative hospitalization rate was 60.0 per 100,000 population.
This cumulative hospitalization rate is the second highest cumulative in-season
hospitalization rate observed in week 9 during previous seasons going back to
2010-2011, following the 2017-2018 season. However, this in-season cumulative
hospitalization rate is similar to the end-of-season hospitalization rates for 4
seasons (2014-2015, 2016-2017, 2018-2019, and 2019-2020 seasons) and lower than
the end-of-season hospitalization rate for the 2017-2018 season, going back to
2010-2011.

When examining rates by age, the highest rate of hospitalization per 100,000
population was among adults aged 65 and older (178.6). Among adults aged 65 and
older, rates were highest among adults aged 85 and older (326.8). Among persons
aged <65 years, hospitalization rates per 100,000 population were highest among
children aged 0-4 years (78.4), followed by adults aged 50-64 years (64.6). When
examining rates by race and ethnicity, the highest rate of hospitalization per
100,000 population was among non-Hispanic Black persons (85.1), followed by
non-Hispanic American Indian or Alaska Native persons (69.4), non-Hispanic White
persons (50.6), Hispanic/Latino persons (46.1), and non-Hispanic Asian/Pacific
Islander persons (25.8).

Among 17,565 hospitalizations, 17,007 (96.8%) were associated with influenza A
virus, 380 (2.2%) with influenza B virus, 26 (0.1%) with influenza A virus and
influenza B virus co-infection, and 152 (0.9%) with influenza virus for which
the type was not determined. Among 4,076 hospitalizations with influenza A
subtype information, 3,081 (75.6%) were A(H3N2), and 995 (24.4%) were
A(H1N1)pdm09. Based on preliminary data, of the 12,746 laboratory-confirmed
influenza-associated hospitalizations with more complete data, 3.9% (95% CI:
3.1%-4.7%) also tested positive for SARS-CoV-2.

Among 2,912 hospitalized adults with information on underlying medical
conditions, 96.9% had at least one reported underlying medical condition, the
most commonly reported were hypertension, cardiovascular disease, metabolic
disorder, and obesity. Among 786 hospitalized women of childbearing age (15-49
years) with information on pregnancy status, 37.8% were pregnant. Among 1,034
hospitalized children with information on underlying medical conditions, 63.7%
had at least one reported underlying medical condition; the most commonly
reported was asthma, followed by obesity, and neurologic disease.

View Full Screen

View Full Screen

--------------------------------------------------------------------------------

Additional FluSurv-NET hospitalization surveillance information for current and
past seasons and additional age groups:
Surveillance Methods |FluView Interactive: Rates by Age, Sex, and Race/Ethnicity
or Data on Patient Characteristics | RESP-NET Interactive


HHS PROTECT HOSPITALIZATION SURVEILLANCE

Hospitals report to HHS Protect the number of patients admitted with
laboratory-confirmed influenza. During week 9, 1,418 patients with
laboratory-confirmed influenza were admitted to a hospital. This was a decrease
of > 5% compared to week 8.


View Chart Data | View Full Screen

--------------------------------------------------------------------------------

Additional HHS Protect hospitalization surveillance information:
Surveillance Methods |  Additional Data


MORTALITY SURVEILLANCE


NATIONAL CENTER FOR HEALTH STATISTICS (NCHS) MORTALITY SURVEILLANCE

Based on NCHS mortality surveillance data available on March 9, 2023, 8.9% of
the deaths that occurred during the week ending March 4, 2023 (week 9), were due
to pneumonia, influenza, and/or COVID-19 (PIC). This percentage remained stable
(< 0.3 percentage point change) compared to week 8 and is above the epidemic
threshold of 7.3% for this week. Among the 2,172 PIC deaths reported for this
week, 876 had COVID-19 listed as an underlying or contributing cause of death on
the death certificate, and 22 listed influenza. While current PIC mortality is
due primarily to COVID-19, the proportion due to influenza increased from
October through mid-December, decreased for seven weeks, and has been stable at
low levels for the past five weeks. The data presented are preliminary and may
change as more data are received and processed.

View Chart Data | View Full Screen

--------------------------------------------------------------------------------

Additional pneumonia, influenza and COVID-19 mortality surveillance information
for current and past seasons:
Surveillance Methods | FluView Interactive


INFLUENZA-ASSOCIATED PEDIATRIC MORTALITY

Eight influenza-associated pediatric deaths occurring during the 2022-2023
season were reported to CDC during week 9. The deaths occurred between week 43
of 2022 (the week ending October 29, 2022) and week 8 of 2023 (the week ending
February 25, 2023). All eight deaths were associated with influenza A viruses.
Four of the influenza A viruses had subtyping performed; all four were A(H3)
viruses.

A total of 125 influenza-associated pediatric deaths occurring during the
2022-2023 season have been reported to CDC.

 View Full Screen 

--------------------------------------------------------------------------------

Additional pediatric mortality surveillance information for current and past
seasons:
Surveillance Methods | FluView Interactive


TREND INDICATORS

Increasing:
Decreasing:
Stable:

INDICATORS STATUS BY SYSTEM

Clinical Labs: Up or down arrows indicate a change of greater than or equal to
0.5 percentage points in the percent of specimens positive for influenza
compared to the previous week.
Outpatient Respiratory Illness (ILINet): Up or down arrows indicate a change of
greater than 0.1 percentage points in the percent of visits due to respiratory
illness (ILI) compared to the previous week.
Long-term Care Facilities: Up or down arrows indicate change of greater than or
equal to 5% of the percent of facilities reporting at least one influenza
positive test among their residents compared to the previous week.
HHS Protect Hospitalizations: Up or down arrows indicate change of greater than
or equal to 5% of the number of patients admitted with laboratory-confirmed
influenza compared to the previous week.
NCHS Mortality: Up or down arrows indicate change of greater than 0.3 percentage
points of the percent of deaths due to PIC compared to the previous week.


ADDITIONAL NATIONAL AND INTERNATIONAL INFLUENZA SURVEILLANCE INFORMATION

FluView Interactive: FluView includes enhanced web-based interactive
applications that can provide dynamic visuals of the influenza data collected
and analyzed by CDC. These FluView Interactive applications allow people to
create customized, visual interpretations of influenza data, as well as make
comparisons across flu seasons, regions, age groups and a variety of other
demographics.

National Institute for Occupational Safety and Health: Monthly surveillance data
on the prevalence of health-related workplace absenteeism among full-time
workers in the United States are available from NIOSH.

U.S. State and local influenza surveillance: Select a jurisdiction below to
access the latest local influenza information.

state links Alabama Alaska Arizona Arkansas California Colorado Connecticut
Delaware District of Columbia Florida Georgia Hawaii Idaho Illinois Indiana Iowa
Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota
Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico
New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode
Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia
Washington West Virginia Wisconsin Wyoming New York City Puerto Rico Virgin
Islands

World Health Organization:
Additional influenza surveillance information from participating WHO member
nations is available through
FluNet and the Global Epidemiology Reports.

WHO Collaborating Centers for Influenza:
Australia, China, Japan, the United Kingdom, and the United States (CDC in
Atlanta, Georgia)

Europe:
The most up-to-date influenza information from Europe is available from
WHO/Europe and the European Centre for Disease Prevention and Control.

Public Health Agency of Canada:
The most up-to-date influenza information from Canada is available in Canada’s
weekly FluWatch report.

Public Health England:
The most up-to-date influenza information from the United Kingdom is available
from Public Health England.

Any links provided to non-Federal organizations are provided solely as a service
to our users. These links do not constitute an endorsement of these
organizations or their programs by CDC or the Federal Government, and none
should be inferred. CDC is not responsible for the content of the individual
organization web pages found at these links.

A description of the CDC influenza surveillance system, including methodology
and detailed descriptions of each data component is available on the
surveillance methods page.


Last Reviewed: March 10, 2023, 11:00 AM
Source: Centers for Disease Control and Prevention, National Center for
Immunization and Respiratory Diseases (NCIRD)
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