Updated project metadata. This project investigates the serum proteomic signatures of the serological response to flu vaccination. We profiled the serum proteome of 160 flu vaccine recipients from a cohort study conducted in 2019-2020 season, with DIA-MS based proteomics. We compared the protein level between low and high responders based on the response measure seroconversion, as well as the adjusted seroconversion which excludes the confoudning effects of all the semographic factors recorded for these participants. We did the analysis for the composite seroconversion as well as for the individual strains. We also investigated the complex impact of age.