Influenza Preparedness and Prevention: 2019-2020 Influenza Season
Michelle Doebler, MPH – Influenza Epidemiologist – MDHHS Division of Immunization
Ten years have passed since the 2009 H1N1 Influenza Pandemic. This anniversary provides an opportunity to reflect on that event and explore the progress that has been made to prevent seasonal influenza as we enter 2019-2020 season. Each year, the Advisory Committee on Immunization Practices (ACIP), utilizes the most up-to-date research to provide annual recommendations on the use of influenza vaccines for the prevention and control of influenza.1 Many of the technologies, surveillance programs, and developments in influenza prevention created in the wake of the 2009 Pandemic assist the ACIP in these important decisions.2
Influenza severity and timing is difficult to predict, but various surveillance programs throughout the United States and in Michigan analyze flu activity throughout the year to determine the burden of flu illness, track potential novel influenza A viruses circulating, and find out when and where influenza activity is occurring. There are five categories of influenza surveillance: viral, mortality, hospitalization surveillance, geographic spread of flu, and the Outpatient Influenza-like Illness Surveillance Network or ILINet. ILINet is a national surveillance system that monitors flu like activity that presents in outpatient appointments.3
The combined efforts of the various surveillance programs demonstrated that the 2018-2019 influenza season was moderately severe with two distinct waves of influenza activity corresponding to two different influenza A viruses circulating throughout the season. Preliminary estimates of national influenza burden for the 2018-2019 season indicate that influenza viruses caused between 37.4 million and 42.9 million illnesses, up to 20.1 million medical visits, 647,000 hospitalizations, and between 36,400 and 61,200 deaths.4 Nationally as of August 10, 2019, 129 influenza-associated pediatric deaths have been confirmed for the 2018-2019 influenza season, 3 of these deaths were from Michigan.5
Since the 2009 Pandemic, developments in influenza prevention and treatment have been substantial. These include but are not limited to new vaccine technologies such as cell-grown and recombinant flu vaccines, research on a universal flu vaccine, and progress in synthetic biology that allows CDC to rapidly generate vaccine viruses against newly emerging flu viruses that may have pandemic potential.2 Progress in influenza vaccine technologies endeavors to improve vaccine effectiveness and reduce the burden of flu illness through prevention.
Receiving an influenza vaccine is the most effective way to prevent flu. Each year influenza vaccination prevents an estimated 1.6-6.7 million illnesses, 790,000-3.1 million medical visits, 39,000-87,000 hospitalizations, and up to 10,000 deaths.6 The 2019-2020 ACIP recommendations for the prevention and control of seasonal influenza with vaccines indicate that all persons aged 6 months and older, without contraindications, should receive an annual flu vaccination.1 However, Michigan’s influenza vaccination coverage estimates for the 2018-2019 season for all persons aged 6 months and older was 30.4% lagging behind the national coverage estimate for the 2017-2018 season of 41.7%. Additionally, among children aged 6 months through 8 years who were recommended to receive 2 doses of influenza vaccine for the season only 12.5% were fully vaccinated. There are many areas where improvements in Michigan’s flu vaccination coverage can be made.
Influenza is not the “stomach flu” but rather is a highly contagious respiratory illness and it is vital that Michigan residents are protected. For more information about influenza vaccination recommendations, visit www.cdc.gov/flu/prevent. To find out where to get a flu vaccination, visit https://vaccinefinder.org/. Get your flu vaccination today!
References:
1 Grohskopf LA, Alyanak E, Broder KR, Walter EB, Fry AM, Jernigan DB. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2019–20 Influenza Season. MMWR Recomm Rep 2019;68(No. RR-3):1–21. DOI: http://dx.doi.org/10.15585/mmwr.rr6803a1
2 Centers for Disease Control and Prevention (CDC). (2019). Summary of Progress since 2009. Retrieved from https://www.cdc.gov/flu/pandemic-resources/h1n1-summary.htm
3 CDC. (2018). Overview of Influenza Surveillance in the United States. Retrieved from https://www.cdc.gov/flu/weekly/overview.htm
4 CDC. (2019). 2018-2019 U.S. Flu Season: Preliminary Burden Estimates. Retrieved from https://www.cdc.gov/flu/about/burden/preliminary-in-season-estimates.htm
5 CDC. (2019). Weekly U.S. Influenza Surveillance Report. Retrieved from https://www.cdc.gov/flu/weekly/index.htm#ILIMap
6 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;12:132–7. DOI: https://doi.org/10.1111/irv.12486