Overall pooled VE was 39% in preventing flu-associated outpatient visits.
For the first time, the mid-season report from four VE networks covers both pediatric and adult age groups.
The group again recommended trivalent vaccine versions, given that 1 of the 2 influenza B strains hasn't been detected since 2020.
Data across 9 flu seasons reveal that flu vaccine effectiveness wanes 9% every 28 days beginning 41 days post-vaccination in adults but not in kids.
October flu vaccinations were greater in children with October births compared with other birth months, with 49% of those born in October also vaccinated in October.
Vaccine halved risk of medically attended COVID, reduced H1N1 flu risk by 60%.
Trends favoring QIV-HD versus QIV-SD were observed over time, even before the flu season was under way.
The researchers say healthcare providers, public health officials must encourage vaccination, especially for those at highest risk.
Maternal flu vaccination was 19% effective against infant emergency department visits.
The recombinant vaccine didn't offer significantly more protection against flu-related hospitalization beyond the standard-dose vaccines.
