A literature review found pneumococcal conjugate vaccines were associated with some protection against flu and other viral respiratory tract infections.
The Yamagata flu B lineage hasn't been confirmed since March 2020 and is no longer thought to pose a health threat.
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.