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How many people died from the flu?

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  • Gordon, A. and Reingold, A. (2018). Influenza Burden: A Complex Problem. Current Epidemiology Reports, 5(1), 1–9. https://doi.org/10.1007/s40471-018-0136-1

  • Charbonneau, DH and James, LN (2019). FluView and FluNet: Tools for Flu Activity and Surveillance. Medical Reference Services Quarterly, 38(4), 358-368. https://doi.org/10.1080/02763869.2019.1657734

  • Macias, AE, McElhaney, JE, Chaves, SS, Nealon, J., Nunes, MC, Samson, SI, Seet, BT, Weinke, T., & Yu, H. (2021). Disease burden of influenza beyond respiratory illness. Vaccine, 39, A6–A14. https://doi.org/10.1016/j.vaccine.2020.09.048

  • Paget J, Spreeuwenberg P, Charu V, Taylor RJ, Iuliano AD, Bresee J, Simonsen L, Viboud C; Global Seasonal Flu-related Mortality Collaborative Network and GLaMOR Collaborative Teams*. Global mortality associated with seasonal flu epidemics: new burden estimates and estimators from the GLaMOR Project. J Glob Health. 2019 Dec;9(2):020421. doi: 10.7189/jogh.09.020421. https://pubmed.ncbi.nlm.nih.gov/31673337/

    This represents the average estimate of annual influenza deaths from 2002-2011, excluding the 2009 “swine flu” pandemic flu season.

    Other global estimates of seasonal flu deaths were made by the Institute for Health Metrics and Evaluation (IHME) and the Centers for Disease Control and Prevention (CDC).

    The estimates made by GLaMOR were comparable to those made by the CDC, while the estimates made by IHME were 4-5 times lower. This may be because IHME estimates influenza mortality by first estimating the number of deaths caused by lower respiratory tract diseases, then estimating the fraction of those primarily attributed to influenza in vital records, oral autopsies, and other death data. This approach would have missed many deaths from flu complications, and deaths that were not recorded in the record as being caused by flu due to limited testing.

    Both the CDC and GLaMOR’s models may be underestimating the overall burden of death from influenza, as they only use data from respiratory-related deaths. While this request For example, it includes deaths from influenza, which is listed as a secondary cause of death on death certificates, request To miss some are caused by influenza but attributed to another cause, such as cardiovascular disease. If these models used all-cause deaths to predict deaths from influenza, they would be more sensitive (they would catch more deaths from flu) but also less specific (they would catch more deaths from other diseases that are not easily distinguishable).

    Compared to CDC estimates, GLaMOR used several country-specific indicators to estimate seasonal influenza mortality for countries that do not provide weekly or monthly influenza mortality records or influenza surveillance data; The CDC estimated this mainly using the WHO Global Health Estimates. respiratory mortality.

  • Eurostat. (2022). Causes of death—Standardized death rate. European Commission. https://ec.europa.eu/eurostat/databrowser/view/HLTH_CD_ASDR2__custom_3500876/default/table?lang=en
    Transport accidents are counted under ICD-10 (V01–V99, Y85). In the 27 EU countries, these rates were 9.02, 9.15 and 8.77 per 100,000 people over 65 in 2015, 2016 and 2017, respectively.

    ICD-10 estimates for mortality from influenza are much lower because they only consider deaths where influenza is listed as a cause of death on death certificates, while the estimates we show above include those indirectly caused by influenza. This means that ICD-10 death rates would be rather underestimated for the flu. However, deaths from traffic accidents are more likely to be listed as the primary cause of death on death certificates and are far less underestimated by death certificate data.

  • Acosta, E., Hallman, SA, Dillon, LY, Ouellette, N., Bourbeau, R., Herring, DA, Inwood, K., Earn, DJD, Madrenas, J., Miller, MS, and Gagnon, A. ( 2019). Determinants of Influenza Mortality Trends: Age-Period-Cohort Analysis of Influenza Mortality in the United States, 1959–2016. demography, 56(5), 1723-1746. https://doi.org/10.1007/s13524-019-00809-y

    The number of deaths from influenza from 1960 to 2015 was estimated using a Serfling model, which estimates the excess number of deaths during flu seasons, using data from the rest of the year and taking into account year-to-year changes. Since 1997, routine testing for “flu-like illnesses” has also been carried out in hospitals to determine the share of those actually caused by the flu rather than other illnesses. Therefore, estimates from 1997 to 2015 were also calculated using a Serfling-surveillance model, which explains the share of tests positive for influenza. This also confirms the predictions from the normal Serfling model. Also, deaths among children under 5 years of age were excluded in both models, as they are likely to include deaths from respiratory syncytial virus.

    The death rate in the US was slightly lower during the 2009 swine flu pandemic season than during regular flu seasons, as severe disease shifted from the elderly to young and middle-aged adults. However, the 2009 Swine flu epidemic led to more deaths than in normal flu seasons in other countries, such as Mexico.

    Gagnon, A., Acosta, E., Hallman, S., Bourbeau, R., Dillon, LY, Ouellette, N., Earn, DJD, Herring, DA, Inwood, K., Madrenas, J., & Miller, MS (2018). The Pandemic Paradox: Early Life H2N2 Pandemic Influenza Infection Increased Susceptibility to Death During the 2009 H1N1 Pandemic. MBio, 9(1), e02091-17. https://doi.org/10.1128/mBio.02091-17

  • Influenza viruses are thought to be transmitted more efficiently in winter due to lower temperature and humidity. But flu outbreaks in many tropical countries coincide with warm rainy seasons, so there may be more reasons for the trends. Other explanations include seasonal changes in human immunity or changes in human behavior such as greater indoor mixing and crowding. Petrova, VN and Russell, CA (2018). Evolution of seasonal influenza viruses. Nature Reviews Microbiology, 16(1), 47-60. https://doi.org/10.1038/nrmicro.2017.118

  • Between 1860 and 1900, there was a slight increase in the risk of death from the flu, which could result from worsening health conditions as more people moved to crowded urban areas.

    Acosta, E., Hallman, SA, Dillon, LY, Ouellette, N., Bourbeau, R., Herring, DA, Inwood, K., Earn, DJD, Madrenas, J., Miller, MS, and Gagnon, A. ( 2019). Determinants of Influenza Mortality Trends: Age-Period-Cohort Analysis of Influenza Mortality in the United States, 1959–2016. Demography, 56(5), 1723-1746. https://doi.org/10.1007/s13524-019-00809-y

  • Cutler, D. and Miller, G. (2005). The role of public health improvements in advances in health: the twentieth century United States. demography, 42(1), 1-22. https://doi.org/10.1353/dem.2005.0002

  • Barberis, I., Myles, P., Ault, SK, Bragazzi, NL, and Martini, M. (2016). The history and evolution of influenza control by vaccination: from the first monovalent vaccine to universal vaccines. Journal of Preventive Medicine and Hygiene, 57(3), E115–E120. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5139605/

  • Centers for Disease Control and Prevention and the National Center for Immunization and Respiratory Diseases. (2021). Historical Reference of Distributed Seasonal Flu Vaccine Doses. https://www.cdc.gov/flu/prevent/vaccine-supply-historical.htm

  • These estimates are more variable for younger age groups, especially those born after 1990, because the number of influenza deaths was low for comparison, especially since deaths in children under 5 were excluded from the models to avoid counting deaths from respiratory syncytial virus.
    Acosta, E., Hallman, SA, Dillon, LY, Ouellette, N., Bourbeau, R., Herring, DA, Inwood, K., Earn, DJD, Madrenas, J., Miller, MS, and Gagnon, A. ( 2019). Determinants of Influenza Mortality Trends: Age-Period-Cohort Analysis of Influenza Mortality in the United States, 1959–2016. demography, 56(5), 1723-1746. https://doi.org/10.1007/s13524-019-00809-y

  • Metcalf, CJE, Paireau, J., O’Driscoll, M., Pivette, M., Hubert, B., Pontais, I., Nickbakhsh, S., Cummings, DAT, Cauchemez, S., & Salje, H. (2022). Comparison of age and sex trajectories of SARS-CoV-2 morbidity and mortality with other respiratory pathogens. Royal Society Open Science, 9(6), 211498. https://doi.org/10.1098/rsos.211498

    In this article, we show the relative risks of death. This is because it is more difficult to give an absolute risk of death from the flu at different ages because, as we have seen, mortality rates vary greatly over time and between countries. Absolute risks depend on how many people are infected during a flu season, availability of healthcare, vaccination rates, etc. it depends. However relative The risk of death—the ratio of the risk of death in one age group versus another—tends to be more consistent.

  • The shape of this age-death curve is usually described by the Gompertz function. Olshansky, SJ and Carnes, BA (1997). Since Gompertz. demography, 34(1), 1-15. https://link.springer.com/content/pdf/10.2307/2061656.pdf

  • Belongia, EA, Simpson, MD, King, JP, Sundaram, ME, Kelley, NS, Osterholm, MT, and McLean, HQ (2016). Variable influenza vaccine efficacy by subtype: A systematic review and meta-analysis of test-negative design studies. Lancet Infectious Diseases, 16(8), 942-951. https://doi.org/10.1016/S1473-3099(16)00129-8

  • Tricco, AC, Chit, A., Soobiah, C., Hallett, D., Meier, G., Chen, MH, Tashkandi, M., Bauch, CT, & Loeb, M. (2013). Comparison of influenza vaccine efficacy against incompatible and matched strains: A systematic review and meta-analysis. BMC Medicine, 11th(1), 153. https://doi.org/10.1186/1741-7015-11-153

  • P. Spreeuwenberg; et al. (December 1, 2018). “Reassessing the Global Mortality Burden of the 1918 Influenza Pandemic”. American Journal of Epidemiology. 187 (12): 2561–2567. doi:10.1093/aje/kwy191. PMID 30202996. Online here.

  • Paget J, Spreeuwenberg P, Charu V, Taylor RJ, Iuliano AD, Bresee J, Simonsen L, Viboud C; Global Seasonal Flu-related Mortality Collaborative Network and GLaMOR Collaborative Teams*. Global mortality associated with seasonal flu epidemics: new burden estimates and estimators from the GLaMOR Project. J Glob Health. 2019 Dec;9(2):020421. doi: 10.7189/jogh.09.020421. https://pubmed.ncbi.nlm.nih.gov/31673337/

  • Worobey, M., Han, G.-Z. and Rambaut, A. (2014). Origin and pathogenesis of the 1918 pandemic H1N1 influenza A virus. Proceedings of the National Academy of Sciences, 111(22), 8107-8112. https://doi.org/10.1073/pnas.1324197111
    Gagnon, A., Miller, MS, Hallman, SA, Bourbeau, R., Herring, DA, Earn, DJD, & Madrenas, J. (2013). Age-specific mortality during the 1918 flu pandemic: Unraveling the mystery of the high young adult mortality rate. PloS One, 8(8), e69586. https://doi.org/10.1371/journal.pone.0069586
    Luk, J., Gross, P., and Thompson, WW (2001). Observations on Mortality During the 1918 Influenza Pandemic. Clinical Infectious Diseases, 33(8), 1375-1378. https://doi.org/10.1086/322662

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