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Feb 28, 2024 · While the effects of flu varies, it places a substantial burden on the health of people in the United States each year. CDC estimates that flu has resulted in 9.3 million – 41 million illnesses, 100,000 – 710,000 hospitalizations and 4,900 – 51,000 deaths annually between 2010 and 2023.
- Past Seasons
These pages includes information about the estimated burden...
- How CDC Estimates Burden
The burden of influenza on the United States can vary widely...
- Preliminary Burden Estimates
The cumulative burden of flu is an estimate of the number of...
- Frequently Asked Questions
Links to key resources on the burden of influenza - CDC....
- CDC
Estimates of the burden of flu in the U.S. help to...
- People at Higher Risk of Flu Complications
Pregnant people and people up to 2 weeks after the end of...
- Weekly Report
CDC estimates that there have been at least 34 million...
- Past Seasons
- Overview
- 2021–2022 Burden Estimates
- Why did the estimates for the 2021-2022 flu season change compared with previous estimates for this season?
- Burden Estimates Limitations
- Tables
- References:
On This Page
•2021–2022 Burden Estimates
•Burden Estimates Limitations
•Tables
•References
The overall burden of influenza (flu) for the 2021-2022 season was an estimated 9.4 million flu illnesses, 4.3 million flu-related medical visits, 100,000 flu-related hospitalizations, and 4,900 flu deaths (Table 1).
Since the emergence of SARS-CoV-2, influenza activity has been lower than observed before the pandemic. Compared with influenza seasons prior to pandemic, the 2021–2022 influenza season was mild and occurred in two waves, with a higher number of hospitalizations in the second wave. Influenza activity in the United States during the 2021–2022 season began to increase in November, declined in January 2022, increased again in March 2022 and remained elevated until mid-June 2022. The season was characterized by two distinct waves and predominately influenza A virus circulation. Overall, influenza A(H3N2) viruses were the most commonly detected influenza viruses this season. The 2021-22 season is described as having low severity**; however, the effect of influenza differed by age group and the severity of the season in some age groups was higher– hospitalization rates among older adults aged ≥65 years old were higher compared with other age groups (5).
CDC estimates that the burden of illness during the 2021–2022 season was low with an estimated 9.4 million people sick with flu, 4.3 million visits to a health care provider for flu, 100,000 hospitalizations for flu, and 4,900 flu deaths (Table 1). The number of cases of influenza-associated illness, medically attended illnesses, hospitalizations, and deaths were the lowest since the 2011-2012 season which was the first full season following the influenza A(H1N1)pdm09 pandemic (6). Adoption of mitigation measures intended to prevent the spread of COVID-19 may have also impacted the timing or severity of influenza activity during the 2021-2022 season.
CDC’s estimates of hospitalizations and mortality associated with the 2021–2022 influenza season show that despite the co-circulation of SARS-CoV-2 and other respiratory viruses, influenza viruses do still cause severe disease and death. Older adults accounted for 84% of deaths, which is similar to recent seasons before the COVID-19 pandemic. These findings continue to highlight the fact that older adults are particularly vulnerable to severe disease with influenza virus infection and that influenza prevention measures such as vaccination are important to reducing the impact of the seasonal epidemics on the population and healthcare system.
Deaths in children with laboratory-confirmed influenza virus infection have been a reportable disease in the United States since 2004; 49 deaths were reported for the 2021-22 season as of October 31, 2023. Although it is possible that reported deaths may under-estimate the true number of deaths for this age group, no deaths in children (aged <18 years) were observed through the Influenza Hospital Surveillance Network (FluSurv-NET) during the 2021-2022 influenza season. As a result, it was not possible to estimate deaths in this age group.
Conclusion
During the 2021-2022 influenza season, CDC estimates that influenza was associated with 9.4 million illnesses, 4.3 million medical visits, 100,000 hospitalizations, and 4,900 deaths. The influenza burden was similar to the burden observed during the 2011-2012 season.
CDC’s model used to estimate the burden of flu includes information collected about flu testing practices and vital records death data. Because current testing and death data were not available at the time of estimation (it takes approximately two years to finalize information on flu testing practices), the estimates that were previously published on the CDC website were made using testing information from prior flu seasons.
The 2021-2022 burden estimates are still preliminary and may change as more information for the season becomes available.
These estimates are subject to some limitations.
*Some of the data used to calculate burden estimates are incomplete or not yet available. These estimates will change as those data become available and the estimates are updated.
**No pediatric deaths were reported in the surveillance system used to estimate the flu death burden; thus, our model was unable to estimate any pediatric deaths due to flu during the 2021-22 season [the Influenza Hospital Surveillance Network (FluSurv-NET)]. However, 49 pediatric deaths (as of October 31, 2023) were reported through a different surveillance system for reporting of pediatric deaths due to flu (the Influenza-associated Pediatric Mortality Surveillance System).
1.Reed C, Chaves SS, Daily Kirley P, Emerson R, Aragon D, Hancock EB, et al. Estimating influenza disease burden from population-based surveillance data in the United States. PLoS One. 2015;10(3):e0118369.
2.Rolfes MA, Foppa IM, Garg S, et al. Annual estimates of the burden of seasonal influenza in the United States: A tool for strengthening influenza surveillance and preparedness. Influenza Other Respir Viruses 2018; 12(1): 132–7.
3.Centers for Disease Control and Prevention. Estimated influenza illnesses and hospitalizations averted by influenza vaccination – United States, 2012-13 influenza season. MMWR Morb Mortal Wkly Rep. 2013 Dec 13;62(49):997-1000.
4.Reed C, Kim IK, Singleton JA, Chaves SS, Flannery B, Finelli L, et al. Estimated influenza illnesses and hospitalizations averted by vaccination–United States, 2013-14 influenza season. MMWR Morb Mortal Wkly Rep. 2014 Dec 12;63(49):1151-4.
5.Merced-Morales A, Daly P, Abd Elal AI, et al. Influenza Activity and Composition of the 2022–23 Influenza Vaccine — United States, 2021–22 Season. MMWR Morb Mortal Wkly Rep 2022;71:913–919. DOI: http://dx.doi.org/10.15585/mmwr.mm7129a1
6.Update: Influenza Activity — United States, 2011–12 Season and Composition of the 2012–13 Influenza Vaccine https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6122a4.htm
Oct 20, 2022 · Globally, seasonal influenza kills an average of 700,000 people each year from respiratory disease or cardiovascular disease. During large flu pandemics, when influenza strains evolved substantially, the death toll was even higher.
How many people die from the flu? The risk of death from influenza has declined over time, but globally, hundreds of thousands of people still die from the disease each year. What you should know about this data
Dec 6, 2023 · The CDC estimates that between 12,000 and 52,000 people died of the flu annually between 2010 and 2020. The 2017–18 flu season had more related deaths than any other season: an estimated 52,000. According to CDC data, the flu led to 15 million medical visits, over 360,000 hospitalizations, and 21,410 deaths during the 2022–23 season.
Dec 13, 2017 · As many as 646,000 people may die from influenza each year worldwide, according to the latest estimates from the Centers for Disease Control and Prevention -- a larger number than what other...
