Mpox CEM study

Primary objectives

• To estimate the incidence of serious adverse events (SAEs) in all enrolled vaccinated individuals after each MPOX vaccine dose, by MPOX vaccine brand.
• To estimate the local and systemic reactogenicity and other common AEFIs occurring within 14 days following each mpox vaccine dose within a subset of participants (‘reactogenicity subset’), by mpox vaccine brand.

Secondary objectives

• To estimate the incidence of adverse events of special interest (AESIs) that result in hospitalisation in all enrolled vaccinated individuals after each Mpox vaccine dose, by Mpox vaccine brand.
• Characterize and estimate the incidence of maternal, perinatal and outcomes in women intentionally or inadvertently exposed to Mpox vaccine during pregnancy and exposure in the breastfed neonate/infant.
• Characterize and estimate the incidence of AEFIs in immunocompromised individuals and children and adolescents who have been given the Mpox vaccine.
• To estimate the incidence of any adverse event, regardless of the severity, after each Mpox vaccine dose, by Mpox vaccine brand.

Study period: 3 months after the last dose of one of the Mpox vaccines.

Follow-up: All participants completed questionnaires through telephone calls at weekly intervals in the first month (D7, D14, D21 and D28, with D0 being the day of vaccination), and once monthly for the two remaining months (D56 and D84) after each vaccine dose administration. Participants in the reactogenicity subset were followed up at additional timepoints in the first 14 days after each dose (D1, D4, D7 and D14, with D0 being the day of vaccination).

Data collection: On a smartphone using a mobile app (ODK Collect). Sample size: 30,000 participants (with a reactogenicity subset of 1,000 per vaccine).