Smallpox Vaccine for Mpox Post-Exposure Prophylaxis: A Cluster RCT

Phase 4

Not yet recruiting

• Conditions: Monkeypox
• Interventions: Drug: Bavarian Nordic smallpox vaccine; Drug: Typhoid VI Polysaccharide Vaccine Injectable Solution

• Registration Number: NCT05745987
• Lead Sponsor: McMaster University

Brief Summary

A cluster randomized controlled trial to determine if smallpox vaccine reduces secondary cases and symptom severity in persons exposed to mpox.

Detailed Description

A pragmatic, adaptive, multi-site, cluster randomized trial where households with one or more persons confirmed to have mpox will be randomized to smallpox vaccine or control. The co-primary outcomes are RT-PCR confirmed mpox and symptom severity.

Study Timeline

• Study First Submitted: 2023-02-10
• Study First Submitted QC: 2023-02-16
• Study First Posted: 2023-02-27
• Status Verified: 2024-05
• Last Update Submitted: 2024-05-21
• Last Update Posted: 2024-05-22
• Study Start: 2024-09-01
• Primary Completion: 2024-12-01
• Study Completion: 2024-12-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 1560

Inclusion Criteria

1. Household member of person with laboratory confirmed mpox
2. Age ≥ 2 years
3. Within 14 days of onset of illness in mpox index case

Exclusion Criteria

1. Pregnancy
2. Breastfeeding
3. Past serious allergic reaction to study vaccine components
4. Previous smallpox vaccination
5. Current or planned use of another investigational drug at any point during study participation

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Smallpox vaccine	Bavarian Nordic smallpox vaccine	Participants will receive the Bavarian Nordic smallpox vaccine 0.5 ml single-dose
Typhoid vaccine	Typhoid VI Polysaccharide Vaccine Injectable Solution	Participants will receive the Typhim Vi® typhoid vaccine 0.5 ml single-dose

Primary Outcome Measures

Name	Time	Method
PCR-confirmed Mpox	4 weeks	To evaluate if smallpox vaccine vs control prevents RT-PCR confirmed mpox
Symptom severity	4 weeks	To evaluate if smallpox vaccine vs control affects symptom severity

Secondary Outcome Measures

Name	Time	Method
Number of skin lesions	8 weeks	To assess the number of skin lesions for any participants who develop mpox
Mpox Pain	8 weeks	To assess pain using an adapted Zoster Brief Pain Inventory
Hospitalization	8 weeks	To determine all cause hospitalization over the study period
Mortality	8 weeks	To determine all cause mortality over the study period
Resolution of skin lesions	8 weeks	To assess the time to resolution (i.e. a new skin layer has formed) of any skin lesion
Self-reported Quality of Life	8 weeks	To assess the QOL of participants using the World Health Organization Quality of Life Scale
Mpox complications	8 weeks	To assess longitudinal complications for any participants who develop mpox

Trial Locations

Locations (10)

Catholic University of Bukavu; 🇨🇩 Kinshasa, Bukavu, Congo, The Democratic Republic of the

Federal Medical Center; 🇳🇬 Abuja, Nigeria

University of Abuja Teaching Hospital; 🇳🇬 Abuja, Nigeria

University of Ibadan; 🇳🇬 Ibadan, Nigeria

Irrua Specialist Teaching Hospital; 🇳🇬 Irrua, Nigeria

Aminu Kano Teaching Hospital; 🇳🇬 Kano, Nigeria

Lagos University Teaching Hospital; 🇳🇬 Lagos, Nigeria

Niger Delta Teaching Hospital; 🇳🇬 Okolobiri, Nigeria

University of Port Harcourt Teaching Hospital; 🇳🇬 Port Harcourt, Nigeria

Makerere University Lung Institute; 🇺🇬 Kampala, Uganda