This year the focus in WP2 was on measuring immune function after vaccination in the VITAL vaccination study. We were able to investigate the humoral response towards multiple vaccines in youung, middle aged and older adults (age range 28-98). We analyzed the induction of influenza A/H3N2 virus-specific antibody titers and PCV13-specific IgG antibody levels in all participants pre and 28-days post vaccination. We showed a significant induction of the vaccine-specific antibody responses in all age groups, however, the PCV13 vaccination, which was a primary vaccination, resulted in a significantly low level in older adults compared to the other 2 adult groups, while the QIV vaccination, which was a booster vaccination, did not differ between age groups. Interestingly we saw that vaccine-induced humoral immunity is vaccine-type specific, although low response to multiple vaccines was mostly observed for a small group of mainly older male adults.   In addition, we further explored the previously identified immunotypes (cevirgel Aging Cell 2022) for vaccination specific signatures.

Next to antibody response analyses, also the T cell analyses were finished, which showed significant induction of antigen-specific T cells in all age groups, but a decrease of good T-cell responders with age. Furthermore, in-depth immune analyses were initiated to further understand defects in vaccination response.

Finally, the first analyses on the transcriptome at baseline and after flu and pneumovaccination were performed at both the gene and pathway level. Results from this first step of analysis include the rich vaccine specific signature for both vaccines with relevant significant innate and adaptive blood transcriptional modules and with a gradation of responses observed with age groups especially for inflammatory responses. The next steps will consist of integrating the transcriptomic, clinical and all immunoassays data with the objective of defining potential biomarkers of vaccination response.