The Ongoing Threat of Influenza

MDHHS Division of Immunizations - Jennifer Crooker BSPH, CHES & Timothy DeRosia MPH

Influenza activity hit historic lows during the 2020-2021 season coinciding with the outbreak of COVID-19.¹ Public health professionals indicate this can be attributed to increased use of infection control methods including handwashing, masking, physical distancing, and limitations on gatherings. However, influenza remains a major global public health threat. Typical flu seasons have resulted in an estimated 1 billion annual global infections according to the World Health Organization.² In the United States, annual influenza-associated deaths range between 12,000 and 52,000 with a spike of approximately 50,000 deaths occurring in the 2017-2018 season.¹ The 2019-2020 season saw a record 199 influenza-associated pediatric deaths nationwide.³

CDC was unable to issue a flu burden estimate for the 2020-2021 season due to that season’s unusually low activity. However, in the current 2021-2022 flu season, influenza rates across the country are once again on the rise likely associated with relaxed infection control practices and decreasing vaccination rates. According to CDC’s FluView Report for the week ending January 22, “there have been at least 2 million flu illnesses, 20,000 hospitalizations, and 1,200 deaths from flu” so far this season in the United States.⁴ As hospitals continue to face challenges from COVID-19, RSV, and other respiratory illnesses, it is a public health priority to decrease the burden of vaccine-preventable respiratory illnesses in our communities

In Michigan, influenza activity has also increased this season compared with the previous flu season. Michigan’s sentinel laboratory network is reporting elevated influenza A activity in two regions throughout the state as of February 4, 2020.⁵ Additionally, the counties participating in the Influenza Hospitalization Surveillance Project (IHSP) have reported 68 influenza-associated hospitalizations so far for the 2021-2022 flu season, and 11 congregate setting outbreaks in schools and long-term care facilities.⁵ Fortunately, zero influenza-associated pediatric deaths have been reported in Michigan as of February 8, 2022.⁵

CDC recommends annual influenza vaccination for all individuals aged 6 months and older.⁶ Aiming to protect our communities from flu, MDHHS has set a goal for the 2021-2022 flu season to vaccinate at least 4 million individuals for influenza. Just over 3.1 million doses of influenza vaccine have been administered to Michiganders so far for the 2021-2022 flu season.⁷ Early data suggests that nationally 2021-2022 influenza vaccination rates are down for many groups including those at higher risk such as children and pregnant persons.⁴

It is not too late to promote influenza vaccination. CDC recommends influenza vaccination throughout the winter months while influenza viruses are still circulating within the community. Additionally, CDC has stated that individuals can get an influenza vaccine and a COVID-19 vaccine in the same visit, as long as they are due for both vaccines.⁶ Don’t miss opportunities to vaccinate! Developing a culture of immunization and taking all available opportunities to immunize against vaccine-preventable diseases will be key to successful response plans for pandemic influenza, COVID-19, and other respiratory illnesses to protect our health care systems, businesses, and schools.

References:

¹Centers for Disease Control and Prevention (CDC). (2018). Estimated Flu-Related Illnesses, Medical Visits, Hospitalizations and Deaths in the United States 2017-2018 Flu Season. Retrieved from https://www.cdc.gov/flu/about/burden/2017-2018.htm

²World Health Organization (WHO). (2019, March). WHO Launches New Influenza Strategy. Retrieved from https://www.who.int/news/item/11-03-2019-who-launches-new-global-influenza-strategy

³CDC. (2021, June). Pediatric Flu Deaths During 2019-2020 Reach New High. Retrieved from https://www.cdc.gov/flu/spotlights/2020-2021/pediatric-flu-deaths-reach-new-high.htm

⁴CDC. (2022, February). Weekly U.S. Influenza Surveillance Report (FluView). Retrieved from https://www.cdc.gov/flu/weekly/index.htm

⁵Michigan Department of Health and Human Services (MDHHS). (2022, February). Flu Vaccination Dashboard. Retrieved from https://www.michigan.gov/documents/MIFluFocus_1_5_06_146893_7.pdf

⁶CDC. (2022, February). 2021-2022 Flu Season FAQ. Retrieved from https://www.cdc.gov/flu/season/faq-flu-season-2021-2022.htm#anchor_1568638581044

⁷MDHHS. (2022, February). Flu Vaccination Dashboard. Retrieved from https://www.michigan.gov/flu/0,6720,7-321-101697---,00.html