Mpox
Conditions
Keywords
mpox vaccines
Brief summary
The study Mbote-TRAXX evaluates humoral and cellular immune responses in individuals vaccinated against mpox with the MVA-BN or LC16m8 vaccine administered as part of a routine mpox vaccination campaign in Kinshasa, Democratic Republic of the Congo (DRC). Participants will be followed up at multiple time points after vaccination in order to assess the kinetics and durability of the immune response by collection of blood samples. It is planned to include approximately 150 participants vaccinated with MVA-BN and 150 participants vaccinated with LC16m8.
Detailed description
The study Mbote-TRAXX evaluates humoral and cellular immune responses in individuals vaccinated against mpox with the MVA-BN or LC16m8 vaccine administered as part of a routine mpox vaccination campaign in Kinshasa, Democratic Republic of the Congo (DRC). Participants will be followed up at multiple time points after vaccination in order to assess the kinetics and durability of the immune response. It is planned to include approximately 150 participants vaccinated with MVA-BN and 150 participants vaccinated with LC16m8. Participants will be followed up in the clinical trial for a period of 24 months with 6 visits: visit 1 (day 0), visit 2 (day 0 + 28 days), visit 3 (day 0 + 59 days), visit 4 (day 0 + 8 months), visit 5 (day 0 + 16 months) and visit 6 (day 0 + 24 months). The study intervention consists of blood samples. At each visit, 10 mL of blood will be collected, and additional blood samples (20 mL per visit) will be taken from a subgroup of participants.
Interventions
PROCEDUREblood sample collection
10 mL of blood will be collected at every visit and additional 20 mL blood samples will be taken from a subgroup of participants at every visit.
Sponsors
Institute of Tropical Medicine, Belgium
Institut National de Recherche Biomédicale (INRB). Kinshasa, Democratic Republic of Congo
Programme Elargi de Vaccination de République Démocratique du Congo
National Institute of Public Health of the Democratic Republic of the Congo
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Any person aged 18 years old or over at the time of giving informed consent, of any gender * Participant received the MVA-BN or LC16m8 mpox vaccine as part of the national vaccination campaign * Participant has the capacity and willingness to give informed written consent * Participant agrees to adhere to the study's follow-up schedule
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| To estimate the seroconversion rate for neutralising antibodies against the mpox virus (MPXV) 28 days after administration of an mpox vaccine (MVA-BN or LC16m8) | Day 28 after inclusion | Seroconversion 28 days after administration of an mpox vaccine, defined as the appearance of an MPXV neutralizing antibody titer (NT50) greater than or equal to the limit of detection in participants who were seronegative at baseline, or at least a two-fold increase in the antibody titer compared to baseline (Day 0) in participants who were seropositive at inclusion |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| 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). | Day 59 and Month 8 | 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. |
| 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). | Day 0, Day 28, Day 59 and Month 8 | 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). |
| 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). | Day 0, Day 28, Day 59, Month 8, Month 16 and Month 24 | 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. |
| 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). | Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 | 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. |
| 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). | Day 0, Day 28, Day 59, and Month 8 | 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). |
| 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). | Day 0, Day 28, Day 59, Month 8, Month 16, and Month 24 | 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). |
| To evaluate the tolerability of MVA-BN and LC16m8 vaccines in terms of solicited symptoms occurring up to 28 days after vaccination. | Day 28 | 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. |
| To document post-vaccination mpox virus infections after administration of an mpox vaccine (MVA-BN or LC16m8). | Month 24 | Number of post-vaccination mpox infections. Post-vaccination mpox infections are defined as any laboratory-confirmed mpox infection occurring after vaccination (assessed anamnesticly). |
Countries
Democratic Republic of the Congo
Outcome results
None listed