Pro-inflammatory cytokine profiles and neutralizing antibodies in JYNNEOS-vaccinated and mpox-diagnosed individuals

Mpox is a significant health concern as an infectious disease. Therefore, understanding the immune response triggered in individuals vaccinated with JYNNEOS and those diagnosed with mpox requires further investigation. In this study, we evaluated neutralizing antibody (nAb) titers and profiles of pro-inflammatory and anti-inflammatory cytokines in JYNNEOS-vaccinated individuals with and without prior exposure to poxvirus, as well as in those who were unvaccinated and diagnosed with mpox. Samples were collected from 23 individuals at multiple time points, before vaccination (D0) and after vaccination (D7, D14, D30, D60, and D150), along with 8 samples from individuals with mpox. We observed a significant increase in nAb titers in naive-vaccinated individuals at D60, followed by a long-term decline at D150. The nAb response was significantly higher in the mpox-diagnosed group compared to the naive-vaccinated group at several time points. However, pre-exposed-vaccinated individuals showed significantly higher nAb titers than those with mpox on D14 and D60. A significant increase in the levels of cytokines IL-6 and IL-8 was detected at D30 in naive-vaccinated individuals. These findings enhance our understanding of the immunogenicity and protective mechanisms induced by JYNNEOS vaccination and highlight a previously unreported pro-inflammatory response as part of the immune repertoire triggered post-vaccination.