Mpox Biology, Outcome, Transmission and Epidemiology - Tracking the Immune Response After mpoX vaCcination (MBOTE-TRAXX): Clinical Study to Monitor the Immunological Response Following Mpox Vaccination in the City of Kinshasa, Democratic Republic of the Congo

To estimate the positivity rate for neutralizing antibodies against MPXV 59 days and 8 months after administration of an mpox vaccine (MVA-BN or LC16m8).

Positivity rate 59 days and 8 months after administration of an mpox vaccine (MVA-BN or LC16m8), defined as the appearance of an MPXV neutralizing antibody titer (NT50) greater than or equal to the limit of detection for participants who were initially seronegative, or by a two-fold increase or more in antibody titer compared with the value at Day 0 in participants who were seropositive at enrollment.

Time frame: Day 59 and Month 8

To analyze the longitudinal evolution of neutralizing antibody titers against MPXV between Day 0, Day 28, Day 59, and Month 8 after administration of an mpox vaccine (MVA-BN or LC16m8).

Neutralizing antibody titers against MPXV measured at Day 0, Day 28, Day 59, and Month 8 after administration of an mpox vaccine (MVA-BN or LC16m8).

Time frame: Day 0, Day 28, Day 59 and Month 8

To estimate the positivity rate for binding antibodies (IgG) against MPXV at all sampling time points: Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8).

Positivity rate at Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8). The positivity rate is defined by the appearance of median fluorescence intensity (MFI) values greater than the limit of detection for participants who were initially seronegative, or by more than a two-fold increase in antibody titer compared with the value at Day 0 for participants who were seropositive at baseline.

Time frame: Day 0, Day 28, Day 59, Month 8, Month 16 and Month 24

To analyze the longitudinal evolution of binding antibody (IgG) titers against MPXV between Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8).

Binding antibody (IgG) titers against MPXV measured at Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8), compared with binding antibody (IgG) titers at Day 0.

Time frame: Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24

To identify factors associated with weak immune responses, measured by the seroconversion rate of neutralizing antibodies at Day 0, Day 28, Day 59, and Month 8 after administration of an mpox vaccine (MVA-BN or LC16m8).

Seroconversion at Day 0, Day 28, Day 59, and Month 8 after administration of an mpox vaccine (MVA-BN or LC16m8). The association between risk factors and neutralizing antibody titers will be assessed using logistic regression (or mixed-effects logistic regression for the longitudinal analysis).

Time frame: Day 0, Day 28, Day 59, and Month 8

To identify factors associated with weak immune responses, measured by the seroconversion rate of binding antibodies (IgG) at Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8).

Seroconversion at Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 after administration of an mpox vaccine (MVA-BN or LC16m8). The association between risk factors and binding antibody (IgG) titers will be assessed using logistic regression (or mixed-effects logistic regression for the longitudinal analysis).

Time frame: Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24

To evaluate the tolerability of MVA-BN and LC16m8 vaccines in terms of solicited symptoms occurring up to 28 days after vaccination.

The frequency of solicited local symptoms (pain, redness, swelling, induration, itching, or a distinct mark \[only for the LC16m8 vaccine\] at the injection site) and solicited systemic symptoms (headache, fatigue, nausea, vomiting, generalized muscle pain, chills, and/or fever greater than or equal to 38.0°C) up to Day 28 after vaccination.

Time frame: Day 28

To document post-vaccination mpox virus infections after administration of an mpox vaccine (MVA-BN or LC16m8).

Number of post-vaccination mpox infections. Post-vaccination mpox infections are defined as any laboratory-confirmed mpox infection occurring after vaccination (assessed anamnesticly).

Time frame: Month 24