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

Mpox is a global disease. Post-exposure prophylaxis with smallpox vaccine has the potential to prevent secondary cases and reduce symptom severity but it has not been proven in a trial to be effective.In this trial, we will randomly select households (as clusters), where each member living with someone diagnosed with monkeypox will receive either the Bavarian Nordic smallpox vaccine or the Typhoid vaccine as post-exposure prophylaxis. We will then see how many people who received the smallpox vaccine versus the typhoid vaccine develop RT-PCR confirmed mpox, and assess symptom severity in these households.

Inclusion Criteria:Household member of person with laboratory confirmed mpoxAge ≥ 10 yearsWithin 14 days of onset of illness in mpox index caseExclusion Criteria:PregnancyBreastfeedingPast serious allergic reaction to study vaccine componentsPrevious smallpox vaccinationCurrent or planned use of another investigational drug at any point during study participation