Smallpox Vaccine for Mpox Post-Exposure Prophylaxis: a Cluster RCT (SMART)

McMaster University

Status and phase: Enrolling; Phase 4

Conditions: Monkeypox

Treatments: Drug: Typhoid VI Polysaccharide Vaccine Injectable Solution; Drug: Bavarian Nordic smallpox vaccine

Study type: Interventional

Funder types: Other

Identifiers

NCT05745987

SMART RCT

Details and patient eligibility

About

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

Full 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.

Enrollment: 1,560 estimated patients

Sex: All

Ages: 2+ years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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1,560 participants in 2 patient groups

Smallpox vaccine

Experimental group

Description:

Participants will receive the Bavarian Nordic smallpox vaccine 0.5 ml single-dose

Treatment:

Drug: Bavarian Nordic smallpox vaccine

Typhoid vaccine

Active Comparator group

Description:

Participants will receive the Typhim Vi® typhoid vaccine 0.5 ml single-dose

Treatment:

Drug: Typhoid VI Polysaccharide Vaccine Injectable Solution