Data suggest the 2024-’25 flu season is past its peak, according to the Centers for Disease Control and Prevention’s (CDC’s) weekly influenza surveillance report. However, 12 more pediatric flu-related deaths were reported for the week ending Feb. 21, bringing the seasonal total to 98.
The CDC also reported this week that its seasonal flu vaccine effectiveness (VE) estimates support continued annual flu vaccinations for all eligible people over 6 months of age.
Hospital visits, outpatient visits and positive flu tests reported to the CDC all decreased over the past two consecutive weeks but remain elevated in what is being called a high-severity flu season, according to the weekly report.
All 12 pediatric deaths reported Friday were associated with influenza A viruses, including eight with A(H1N1), two with A(H3N2), one with a coinfection of both strains and one without subtyping performed.
Latest vaccination data from the CDC show that 45.8% of children have been immunized against the flu this season. Thursday’s VE report, which included data from four different CDC-affiliated networks, showed this year’s strain was 32%, 59% and 60% effective against any influenza in outpatient settings (three reporting networks) and 63% and 78% effective against flu hospitalizations (two reporting networks) for children and adolescents.
The AAP and CDC recommend everyone 6 months and older get vaccinated against the flu and COVID-19. The vaccines can be given at the same time. In addition, eligible infants, high-risk toddlers, pregnant people and older adults should get immunized against respiratory syncytial virus.
The CDC estimates there have been at least 37 million illnesses, 480,000 hospitalizations and 21,000 deaths from the flu this season.
Encephalopathy report
A CDC Morbidity and Mortality Weekly Report published Thursday addressed anecdotal reports of pediatric flu patients with influenza-associated encephalopathy (IAE), including those who died with acute necrotizing encephalopathy (ANE). Clinicians are advised to consider the possibility of IAE in children with the flu who also present abnormal neurologic signs or symptoms.
Through Feb. 8, nine pediatric flu deaths with IAE were reported to the CDC; four of those had ANE. The CDC does not systematically collect data on IAE and ANE and therefore cannot say whether these numbers deviate from a typical flu season.
“Enhanced surveillance to systematically identify and report pediatric IAE cases, including ANE, in the United States during the remainder of the 2024–25 season would improve understanding of the incidence of this influenza complication and the frequency of severe outcomes, including long-term neurologic sequelae or death,” the report said.
To that end, the CDC calling for its national partners to report possible cases of IAE identified during the 2024-’25 flu season on the Epidemic Information Exchange and to email [email protected] to begin the process.
ANE is a known complication of infection by multiple viruses and is characterized by symmetric lesions on the brain detected by computed tomography or magnetic resonance imaging.
