Vaccine effectiveness against hospital admission for the flu was 40%.
One third of those polled said their vaccine decisions do not affect others.
Up-to-date COVID-19 vaccination coverage was 17% among hospital healthcare personnel and 23% among those at nursing homes.
Giving both at the same visit could boost uptake of both vaccines, the authors said.
Formulations of the combo vaccines prompted robust immune responses against influenza A, influenza B, and SARS-CoV-2.
The company expects an FDA decision in the first quarter of 2024.
The weekly proportion of outpatient visits for influenza-like illness, flu hospitalizations, and flu deaths all peaked between the 90th and 98th percentile.
Previously vaccinated children in a county with the greatest COVID-19 severity had a lower predicted probability of receiving a flu vaccine than those in a county with the lowest severity.
The company said a combo vaccine could streamline immunization for consumers and health providers and make it easier for people to follow public health recommendations.
A naturally occurring Yamagata lineage flu B virus hasn't been confirmed since March 2020 during the early COVID pandemic months.
