CRP and inflammatory response: However, the reasons for decreased vaccine effectiveness in the elderly go far beyond this, that is, it is not only associated with impaired antibody response, decreased T-cell response, and altered antigen presentation of the immune system, but also related to the chronic and systemic aseptic inflammatory state accompanies aging.405 Research conducted by Puzianowska-Kuźnicka et al.406 has shown that two pro-inflammatory cytokines—IL-6 and C-reactive protein (CRP), increase in the elderly in an age-dependent manner, highlighting the connection between chronic inflammation and aging.