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

SMART (Smallpox Vaccine for Mpox Post-Exposure Prophylaxis: A Cluster Randomized Controlled Trial)

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

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.

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