Fig. 4.

Orthopoxvirus-specific IgGs in the serum of study participants immunized either by first- or third-generation vaccines. (A) Total orthopoxvirus-specific IgG of laboratory workers illustrated by units/ml derived from a standard curve. Serum samples included were collected from 2014 to 2021. (B) Comparison of serum orthopoxvirus-specific IgG of laboratory workers grouped according to vaccine administered. (C) Orthopoxvirus-specific IgG levels of serum samples from active laboratory workers collected in 2022. (D) Group comparison of orthopoxvirus-specific IgG levels of serum samples taken in 2022, during the active MPXV outbreak. Statistical significance was determined by Mann-Whitney t-test (**p = 0.0012,0.0027, respectively; p = 0.0513, p = 0.5912, non-significant, ns). Each bar shows an individual study participant, whereas each plotted value represents a different year of serum collection. IgG levels are aligned from highest to lowest concentration. Dashed lines: range of positive control, negative controls: sera from non-immunized laboratory workers.