The burden of influenza in the United States can vary from year to year depending on which viruses are circulating, how many people receive an influenza vaccination, and how effective the vaccination is in that particular year. During the 2019-2020 flu season, around 25,000 people lost their lives to the disease. Although most people recover from influenza without needing medical care, the disease can be deadly among young children, the elderly, and those with weakened immune systems or chronic illnesses.

Deaths due to influenza Even though most people recover from influenza without medical care, influenza and pneumonia can be deadly, especially for older people and those with certain preexisting conditions. Influenza is a common cause of pneumonia and although most cases of influenza do not develop into pneumonia, those that do are often more severe and more deadly. Deaths due to influenza are most common among the elderly, with a mortality rate of around 7.4 per 100,000 population during the 2021-2022 flu season. In comparison, the mortality rate for those aged 50 to 64 years was just 1.2 per 100,000 population.

Flu vaccinations The most effective way to prevent influenza is to receive a yearly influenza vaccination. These vaccines have proven to be safe and are usually cheap and easily accessible. Nevertheless, every year a large share of the population in the United States still fails to get vaccinated against influenza. For example, in the 2021-2022 flu season only 37 percent of those aged 18 to 49 years received a flu vaccination. Unsurprisingly, children and the elderly are the most likely to get vaccinated. It is estimated that during the 2021-2022 flu season vaccinations prevented over 618 thousand influenza cases among children aged 6 months to 4 years.

Influenza, also called the flu, is one of the most infectious diseases worldwide. Its symptoms range from mild to severe, and include sore throat, cough, runny nose, fever, headache, and muscle pain, but can also cause severe illness and death among high-risk populations such as the elderly and children. During the 2022-2023 flu season, there were 31 million cases of influenza in the United States.

Influenza deaths Although influenza does not require medical attention for most people, it can be deadly, and causes thousands of deaths every year. The impact of influenza varies from year to year. The number of influenza deaths during the 2021-2022 flu season was 4,977. The vast majority of deaths attributed to influenza during the 2021-2022 flu season occurred among those aged 65 years and older.

Vaccination An annual influenza vaccination remains the most effective way of preventing influenza. During the 2021-2022 flu season, influenza vaccinations prevented an estimated 867 deaths among U.S. adults aged 65 years and older. Although, flu vaccinations are accessible and cheap, a large share of the United States population still fails to get vaccinated every year. In 2021-2022, only 37 percent of those aged 18 to 49 years received a flu vaccination, much lower compared to children and the elderly.

During the 2022-2023 flu season in the United States, around 21,401 people died from influenza. The vast majority of deaths due to influenza occur among the elderly, with those aged 65 years and older accounting for 15,399 deaths during the 2022-2023 flu season. During this time, the mortality rate from influenza among those aged 65 years and older was around 26.6 per 100,000 population, compared to a mortality rate of .7 per 100,000 population among those aged 18 to 49 years. Influenza deaths Although most people recover from influenza without the need of medical care, influenza and pneumonia are still major causes of death in the United States. Influenza is a common cause of pneumonia and cases in which influenza develops into pneumonia tend to be more severe and more deadly. However, the impact of influenza varies from year to year depending on which viruses are circulating. For example, during the 2017-2018 flu season around 51,000 people died due to influenza, whereas in 2022-2023 total deaths amounted to 21,000. Preventing death The most effective way to prevent influenza is to receive a yearly influenza vaccination. These vaccines have proven to be safe and are usually cheap and easily accessible. Each year, flu vaccinations prevent thousands of influenza cases, hospitalizations and deaths. It was estimated that during the 2022-2023 flu season, vaccinations prevented the deaths of around 2,479 people aged 65 years and older.

List of free flu clinics offered throughout Chicago for the 2019-2020 flu season, either by the Department of Public Health or in collaboration with it.

Limited amounts of high-dose flu vaccines for seniors may be available throughout the season. Check https://www.chicago.gov/city/en/depts/cdph/supp_info/health-protection/flu-clinics-in-the-city-of-chicago.html for updates.

This view and the underlying dataset approximately follow https://github.com/codeforamerica/flu-shot-spec/blob/master/data-format.csv and are designed for use by https://github.com/tkompare/chicagoflushots.

For more information about the flu, go to https://www.cityofchicago.org/city/en/depts/cdph/provdrs/flu.html.

Influenza and pneumonia caused around 12.3 deaths in the U.S. per 100,000 population in 2019. Influenza and pneumonia are among the leading causes of death in the United States, accounting for around 1.6 percent of all deaths in 2020. Influenza, or the flu, is a viral infection that is highly contagious and especially common in the winter season. Influenza is a common cause of pneumonia, although most cases of the flu do not develop into pneumonia. Pneumonia is an infection or inflammation of the lungs and is particularly deadly among young children and the elderly.

Influenza cases

Influenza is very common in the United States, with an estimated 35 million cases reported in 2019-2020. Common symptoms of the flu include cough, fever, runny or stuffy nose, sore throat and headache. Symptoms can be mild but can also be severe enough to require medical attention. In 2019-2020, there were around 16 million influenza-related medical visits in the United States.

Prevention

To prevent contracting the flu people can take everyday precautions such as regularly washing their hands and avoiding those who are sick, but the best way to prevent the flu is by receiving the flu vaccination every year. Receiving a flu vaccination is especially important for young children and the elderly as they are most susceptible to flu complications and associated death. In 2021, around 75 percent of those aged 65 years and older received a flu vaccine, while only 38 percent of those aged 18 to 49 years had done so.

Weekly Cumulative Influenza Vaccination Coverage, by Flu Season and Race/Ethnicity, Medicare Fee-For-Service Beneficiaries aged ≥65 years, United States

• Influenza vaccination coverage among Medicare fee-for-service beneficiaries aged ≥65 years is assessed using data files from the Medicare Fee-For-Service (FFS) administrative claims data managed by the Centers for Medicare & Medicaid Services (CMS).

• Weekly influenza vaccination coverage estimates were calculated using Kaplan-Meier survival analysis, based on beneficiaries enrolled as of August 1, 2019 and followed through May 31, 2020 for 2019-20 flu season; and enrolled as of August 1, 2020 and followed through May 31, 2021 for 2020-21 flu season; and enrolled as of Aug 1, 2021 and followed through May 28, 2022 for the 2021-22 flu season.

• Additional information about data source is available https://www2.ccwdata.org/web/guest/home/.

Weekly Cumulative Influenza Vaccination Coverage Comparison between Current and Previous Season, Children 6 Months through 17 Years, United States

• Influenza vaccination coverage among children is assessed through the National Immunization Survey-Flu (NIS-Flu) annually, providing weekly influenza vaccination coverage estimates for children 6 months–17 years based upon parental report. (https://www.cdc.gov/vaccines/imz-managers/nis/about.html)

o NIS-Flu is a national random-digit-dialed cellular telephone survey of households conducted during the flu season (October-June).

• Additional information about NIS-Flu methods and estimates from the 2019-2020 season are available at: https://www.cdc.gov/flu/fluvaxview/coverage-1920estimates.htm. Final estimates for prior seasons and other flu vaccination data are available at CDC’s FluVaxView.: https://www.cdc.gov/flu/fluvaxview/index.htm.

In November 2019, 47 percent of U.S. adults aged 30 to 44 years reported that they did not plan on getting vaccinated for the upcoming influenza season, compared to 19 percent of adults aged 65 years and older. This statistic shows the proportion of adults who planned on getting an influenza vaccination for the 2019-2020 flu season in the United States, by age.

In 2019, around 37 percent of U.S. adults who did not plan on getting an influenza vaccination for the 2019-20 flu season stated concerns about possible side effects from the vaccine as a major reason. This statistic shows the percentage of U.S. adults who did not plan to get an influenza vaccination for the 2019-2020 flu season for select reasons.

FluWatch is Canada's national surveillance system that monitors the spread of influenza and influenza-like illnesses on an ongoing basis. FluWatch reports, posted every Friday, contain information on flu activity in Canada. The FluWatch program consists of a network of labs, hospitals, doctor's offices and provincial and territorial ministries of health. Program objectives are: •DETECT: Identify signals to detect, assess and respond to epidemics and other events of public health concern. •INFORM: Contribute to the evidence base necessary to plan, develop and implement health programs and policies for the control of influenza. •ENABLE: Support national infrastructure for influenza surveillance, including national and international collaborations related to surveillance and pandemic response. FluWatch consists of seven surveillance systems components and together they provide a national picture of influenza activity in Canada.

This dataset includes aggregated weekly respiratory virus laboratory data that the Chicago Department of Public Health (CDPH) uses to monitor influenza, COVID-19, respiratory syncytial virus (RSV), and other respiratory virus activity in Chicago. The data represents respiratory viral PCR tests performed by several hospital laboratories in Chicago as well as two commercial laboratories serving Chicago facilities. Data are voluntarily reported on a weekly basis and do not contain patient demographic or geographic information. The data reported represent both Chicago and non-Chicago residents tested by the reporting facility. The respiratory viruses included are influenza, RSV, SARS-CoV-2, parainfluenza, rhinovirus/enterovirus, adenovirus, human metapneumovirus, and seasonal coronaviruses. Influenza laboratory data are available from 2010-2011 to present; for all other respiratory viruses data are available from 2019-2020 to present. All data are provisional and subject to change. Information is updated as additional details are received. At any given time, this dataset reflects data currently known to CDPH. Numbers in this dataset may differ from other public sources.

NNDSS - TABLE 1R. Hepatitis C, perinatal infection to Influenza-associated pediatric mortality - 2020. In this Table, provisional cases* of notifiable diseases are displayed for United States, U.S. territories, and Non-U.S. residents. Notice: Data from California published in week 29 for years 2019 and 2020 were incomplete when originally published on July 24, 2020. On August 4, 2020, incomplete case counts were replaced with a "U" indicating case counts are not available for specified time period. Note: This table contains provisional cases of national notifiable diseases from the National Notifiable Diseases Surveillance System (NNDSS). NNDSS data from the 50 states, New York City, the District of Columbia and the U.S. territories are collated and published weekly on the NNDSS Data and Statistics web page (https://wwwn.cdc.gov/nndss/data-and-statistics.html). Cases reported by state health departments to CDC for weekly publication are provisional because of the time needed to complete case follow-up. Therefore, numbers presented in later weeks may reflect changes made to these counts as additional information becomes available. The national surveillance case definitions used to define a case are available on the NNDSS web site at https://wwwn.cdc.gov/nndss/. Information about the weekly provisional data and guides to interpreting data are available at: https://wwwn.cdc.gov/nndss/infectious-tables.html. Footnotes: U: Unavailable — The reporting jurisdiction was unable to send the data to CDC or CDC was unable to process the data. -: No reported cases — The reporting jurisdiction did not submit any cases to CDC. N: Not reportable — The disease or condition was not reportable by law, statute, or regulation in the reporting jurisdiction. NN: Not nationally notifiable — This condition was not designated as being nationally notifiable. NP: Nationally notifiable but not published. NC: Not calculated — There is insufficient data available to support the calculation of this statistic. Cum: Cumulative year-to-date counts. Max: Maximum — Maximum case count during the previous 52 weeks. * Case counts for reporting years 2019 and 2020 are provisional and subject to change. Cases are assigned to the reporting jurisdiction submitting the case to NNDSS, if the case's country of usual residence is the U.S., a U.S. territory, unknown, or null (i.e. country not reported); otherwise, the case is assigned to the 'Non-U.S. Residents' category. Country of usual residence is currently not reported by all jurisdictions or for all conditions. For further information on interpretation of these data, see https://wwwn.cdc.gov/nndss/document/Users_guide_WONDER_tables_cleared_final.pdf. †Previous 52 week maximum and cumulative YTD are determined from periods of time when the condition was reportable in the jurisdiction (i.e., may be less than 52 weeks of data or incomplete YTD data). § Please refer to the CDC WONDER publication for weekly updates to the footnote for this condition.

NNDSS - TABLE 1Y. Mumps to Novel influenza A virus infections - 2020. In this Table, provisional cases* of notifiable diseases are displayed for United States, U.S. territories, and Non-U.S. residents.

Notice: Data from California published in week 29 for years 2019 and 2020 were incomplete when originally published on July 24, 2020. On August 4, 2020, incomplete case counts were replaced with a "U" indicating case counts are not available for specified time period.

Note: This table contains provisional cases of national notifiable diseases from the National Notifiable Diseases Surveillance System (NNDSS). NNDSS data from the 50 states, New York City, the District of Columbia and the U.S. territories are collated and published weekly on the NNDSS Data and Statistics web page (https://wwwn.cdc.gov/nndss/data-and-statistics.html). Cases reported by state health departments to CDC for weekly publication are provisional because of the time needed to complete case follow-up. Therefore, numbers presented in later weeks may reflect changes made to these counts as additional information becomes available. The national surveillance case definitions used to define a case are available on the NNDSS web site at https://wwwn.cdc.gov/nndss/. Information about the weekly provisional data and guides to interpreting data are available at: https://wwwn.cdc.gov/nndss/infectious-tables.html.

Footnotes: U: Unavailable — The reporting jurisdiction was unable to send the data to CDC or CDC was unable to process the data. -: No reported cases — The reporting jurisdiction did not submit any cases to CDC. N: Not reportable — The disease or condition was not reportable by law, statute, or regulation in the reporting jurisdiction. NN: Not nationally notifiable — This condition was not designated as being nationally notifiable. NP: Nationally notifiable but not published. NC: Not calculated — There is insufficient data available to support the calculation of this statistic. Cum: Cumulative year-to-date counts. Max: Maximum — Maximum case count during the previous 52 weeks. * Case counts for reporting years 2019 and 2020 are provisional and subject to change. Cases are assigned to the reporting jurisdiction submitting the case to NNDSS, if the case's country of usual residence is the U.S., a U.S. territory, unknown, or null (i.e. country not reported); otherwise, the case is assigned to the 'Non-U.S. Residents' category. Country of usual residence is currently not reported by all jurisdictions or for all conditions. For further information on interpretation of these data, see https://wwwn.cdc.gov/nndss/document/Users_guide_WONDER_tables_cleared_final.pdf. †Previous 52 week maximum and cumulative YTD are determined from periods of time when the condition was reportable in the jurisdiction (i.e., may be less than 52 weeks of data or incomplete YTD data). § Novel influenza A virus infections are human infections with influenza A viruses that are different from currently circulating human seasonal influenza viruses. With the exception of one avian lineage influenza A (H7N2) virus, all novel influenza A virus infections reported to CDC since 2012 have been variant influenza viruses.

Over 12 million people in the United States died from all causes between the beginning of January 2020 and August 21, 2023. Over 1.1 million of those deaths were with confirmed or presumed COVID-19.

Vaccine rollout in the United States Finding a safe and effective COVID-19 vaccine was an urgent health priority since the very start of the pandemic. In the United States, the first two vaccines were authorized and recommended for use in December 2020. One has been developed by Massachusetts-based biotech company Moderna, and the number of Moderna COVID-19 vaccines administered in the U.S. was over 250 million. Moderna has also said that its vaccine is effective against the coronavirus variants first identified in the UK and South Africa.

In the United States, the highest rate of hospitalizations due to influenza are among those aged 65 years and older. During the 2022-2023 flu season, the rate of hospitalizations due to influenza among this age group was about 332 per 100,000 population, compared to a rate of around 46 per 100,000 for those aged 5 to 17 years. Influenza is a common viral infection that usually does not require medical treatment. However, for the very young, the old, and those with certain pre-existing conditions, influenza can be serious and even deadly.

The burden of influenza in the United States The impact of influenza in the United States varies from year to year depending on the strain that is most prevalent during that season and the immunity in the population. Nevertheless, influenza and pneumonia are often among the top ten causes of death in the United States. Preliminary estimates show that around 21,000 people died from influenza during the 2022-2023 flu season. However, during the 2017-2018 flu season, an estimated 51,000 people lost their lives to influenza.

The importance of flu vaccines The best way to avoid catching the flu and to reduce the virus’s overall burden on society is by receiving an annual flu vaccination. The CDC currently recommends that everyone over 6 months of age should get a flu vaccination every year, preferably by the end of October. The flu vaccine is safe, efficient, and reduces the number of illnesses, hospitalizations, and deaths caused by the virus. For example, during the 2018-2019 flu season it was estimated that vaccinations averted around 58 thousand influenza-related hospitalizations. However, despite the proven benefits and wide availability of flu vaccinations, a large percentage of people in the United States fail to receive a vaccination every year. During the 2021-2022 flu season, only about 37 percent of those aged 18 to 49 years were vaccinated against influenza, compared to 74 percent of those aged 65 years and older.