WEDNESDAY, Oct. 30 2024 (HealthDay News) -- Influenza-associated hospitalization rates vary across seasons, and only returned to recent pre-COVID-19 pandemic levels in the 2022-2023 influenza season, according to research published in the Oct. 31 issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Angelle Naquin, M.P.H., from the CDC in Atlanta, and colleagues conducted a comprehensive summary of trends in hospitalization rates and clinical data collected from the Influenza Hospitalization Surveillance Network for the 2010-2011 through 2022-2023 influenza seasons.
The researchers found that laboratory-confirmed influenza-associated hospitalization rates varied significantly across the 2010-2011 to 2022-2023 seasons. The hospitalization rates ranged from 8.7 to 102.9 (2011-2012 and 2017-2018, respectively) per 100,000 population before the COVID-19 pandemic. The hospitalization rate was 0.8 for 2020-2021 and did not return to recent prepandemic levels until 2022-2023. Adults aged 65 years and older consistently had the highest influenza-associated hospitalization rate in each season, followed by children aged 0 to 4 years in most seasons. Among patients hospitalized with influenza, there was an increase in the prevalence of at least one underlying medical condition with age, ranging from 36.9 to 95.4 percent for children aged 0 to 4 years and adults aged 65 years and older, respectively. During the 2010-2011 to 2017-2018 influenza seasons, antiviral use increased, but then decreased from 90.2 percent during 2018-2019 to 79.1 percent during 2022-2023, especially among children and adolescents.
"Each of these findings are of public health importance on their own but collectively highlight the importance of conducting robust and adaptable annual public health surveillance for influenza-associated hospitalizations," the authors write.