Prospective Follow-up After MVA-BN Booster Vaccination (POQS-Boosted)

January 15, 2026 updated by: Institute of Tropical Medicine, Belgium

Prospective On-site Study for the Immunological Follow-up of Individuals Who Received Booster Vaccination With MVA-BN Against Mpox

POQS-Boosted is a prospective observational study during which individuals who received Booster vaccination against mpox with the MVA-BN vaccine will be invited to provide biological samples at multiple times over the course of two years.

Study Overview

Status

Not yet recruiting

Conditions

Detailed Description

Mpox caused a worldwide outbreak in 2022 and continues to circulate worldwide and causes sporadic cases in Belgium and elsewhere. In the last 10 days, the first cases infected with the probably more virulent clade Ib MPXV have been reported from men who have sex with men in Belgium, the Netherlands, and elsewhere, indicating circulating this viral clade in sexual networks. In Belgium, vaccination against mpox was ceased at the end of 2022 and evidence showed that antibody levels against MPXV have decreased since then, raising questions about sustained protectiveness and the potential for a new mpox outbreak to emerge.

POQS-Boosted is a prospective observational study during which individuals who received Booster vaccination against mpox with the MVA-BN vaccine will be invited to provide biological samples at multiple times over the course of two years.

Study Type

Observational

Enrollment (Estimated)

95

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Christophe Van Dijck, PhD
  • Phone Number: +32 3 345 58 65
  • Email: cvandijck@itg.be

Study Contact Backup

  • Name: Clinical Trials Unit Antwerp
  • Phone Number: +32 3 247 66 66
  • Email: studies@itg.be

Study Locations

  • Belgium
      • Antwerp, Belgium, 2000
        • Institute of Tropical Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Individuals who received MVA-BN booster vaccination will be asked to participate in "POQS-Boosted"

Description

Inclusion Criteria:

  1. Is scheduled to receive a booster dose of MVA-BN
  2. ≥18 years
  3. Willingness to provide written informed consent
  4. Willingness to follow the study schedule

Exclusion Criteria:

1. Past or current MPXV infection

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Orthopoxvirus-specific serum binding and neutralising antibody titre
Time Frame: from enrollment to the end of follow up at 2 years
To describe the evolution of the orthopoxvirus-specific serum antibody response up to two years after MVA-BN booster vaccination
from enrollment to the end of follow up at 2 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Orthopoxvirus-specific systemic T- and B cell-mediated immune responses to MPXV
Time Frame: from enrollment up to 2 years
To describe the evolution of the orthopoxvirus-specific systemic cellular immune response up to two years after MVA-BN booster vaccination
from enrollment up to 2 years
MPXV-specific IgA in saliva and anorectal samples; T and B cell-mediated immune responses to MPXV, measured on saliva and anorectal samples
Time Frame: from enrolment up to two years
To describe the evolution of the orthopoxvirus-specific mucosal antibody & cellular immune response up to two years after MVA-BN booster vaccination
from enrolment up to two years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Institute of Tropical Medicine, Belgium

Investigators

  • Principal Investigator: Laurens Liesenborghs, MD, Institute Of Tropical Medicine Antwerp

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 15, 2026

Primary Completion (Estimated)

June 30, 2028

Study Completion (Estimated)

June 30, 2028

Study Registration Dates

First Submitted

January 6, 2026

First Submitted That Met QC Criteria

January 6, 2026

First Posted (Estimated)

January 15, 2026

Study Record Updates

Last Update Posted (Actual)

January 20, 2026

Last Update Submitted That Met QC Criteria

January 15, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • POQS-Boosted

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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