On Oct. 20, 2023, the U.S. Centers for Disease Control and Prevention (CDC) reported that among children and adolescents aged <18 years, 2022-23 was a high severity influenza season compared with thresholds based on previous seasons’ data; influenza-associated medical visits and hospitalizations met or exceeded incidence in previous seasons.

During the 2022–23 season, influenza activity in the United States began in early October, earlier than in most previous seasons, and returned to pre–COVID-19 levels. In addition, high pediatric influenza hospitalization rates in the southeast, co-circulation of influenza virus with SARS-CoV-2 and respiratory syncytial virus (RSV), and a limited reduction in the availability of the influenza antiviral medication oseltamivir were observed. Each year, CDC assesses seasonal severity by comparing current season’s influenza activity with thresholds based on peak influenza activity in previous seasons and estimates the numbers and rates of influenza-associated medical visits, hospitalizations, and deaths in the United States.

This report describes the 2022–23 influenza season among children and adolescents, including seasonal severity, estimated incidence, and characteristics of hospitalized patients. This analysis focuses on the 2022–23 influenza season compared with 2016–17 through 2021–22, excluding 2020–21 (during the peak of the COVID-19 pandemic) when influenza activity was minimal.

The 2022–23 influenza season was classified as high severity among children and adolescents, the fourth season with that classification since the 2009 influenza A(H1N1) pandemic. Further, all three severity indicators not only surpassed intensity levels for high severity, but the peaks also occurred early in the season (late November and early December) (1). National estimates of the rates of influenza-associated medical visits and hospitalizations were higher than those during most previous seasons for children aged <5 years and children and adolescents aged 5–17 years. This high incidence strained health care systems, particularly with the co-circulation of SARS-CoV-2 and RSV.^†††

Among children and adolescents hospitalized with influenza during 2022–23, a substantially lower proportion were vaccinated compared with previous seasons, which could be related to low vaccination coverage in the population, high vaccine effectiveness, or both. The National Immunization Survey estimates that when pediatric influenza-associated hospitalization rates peaked during the week ending November 26, 2022, only 41.9% of children and adolescents aged 6 months–17 years nationwide had received their annual influenza vaccination (compared with 55.1% by the end of the season). Influenza vaccination coverage by the end of November was similar in 2022 and in 2021 (45.0%), but lower than in 2019 (51.9%) and 2020 (49.7%). Preliminary assessments have shown that the 2022–23 influenza vaccine provided moderately strong (68%) protection against pediatric hospitalization.

The combination of low influenza vaccine coverage early in the season and unusually early influenza activity (57.1% of the season’s pediatric hospitalizations occurred by the end of November) likely contributed to the high observed rate of influenza-associated hospitalization, despite the moderately strong protection from the 2022–23 influenza vaccine. In addition, a lower proportion of symptomatic hospitalized patients in 2022–23 received influenza antiviral medication compared with that during pre–COVID-19 pandemic seasons. Taken together, these findings underscore the importance of children and adolescents receiving a seasonal influenza vaccination, ideally by the end of October, and prompt influenza antiviral treatment for those who are hospitalized

The 2022–23 influenza season was classified as high severity for children and adolescents based on influenza-associated outpatient visits, hospitalization rates, and deaths. Among hospitalized children and adolescents with influenza, receipt of influenza vaccine was lower than that during previous seasons, which might have been in part related to most influenza hospitalizations occurring earlier. The proportion of pediatric hospitalizations treated with influenza antiviral medication was lower than in pre–COVID-19 pandemic seasons; prompt antiviral treatment is important for symptomatic patients hospitalized with influenza. All persons aged ≥6 months are recommended by CDC to receive the annual seasonal influenza vaccine, ideally by the end of October.