Table 1 Trial objectives and endpoints

Primary

• Assess adverse maternal/fetal outcomes in pregnant women randomized to receive the 2-dose Ebola vaccine regimen (Ad26.ZEBOV, MVA-BN-Filo (group A)) and in control women (unvaccinated pregnant women (group B))

• Frequency of maternal death, spontaneous abortion, stillbirth, pathways to preterm birth (premature preterm rupture of membranes, preterm labor, insufficient cervix, provider initiated preterm birth), pre-eclampsia/eclampsia, antenatal bleeding and post-partum hemorrhage from randomization until 6 weeks post-completion/termination of pregnancy

• Assess adverse neonatal/infant outcomes in neonates/infants born to women randomized to receive the 2-dose Ebola vaccine regimen (Ad26.ZEBOV, MVA-BN-Filo (group A)) and in neonates/infants born to control women (unvaccinated pregnant women (group B))

• Frequency of major congenital malformations, small for gestational age (SGA), low birth weight, preterm birth, neonatal death, and failure to thrive in infants measured from birth until 14 weeks of age

Secondary

• Assess safety in pregnant women randomized to receive the 2-dose Ebola vaccine regimen (Ad26.ZEBOV, MVA-BN-Filo group A) and in control women (unvaccinated pregnant women (group B))

• Frequency and relatedness of all SAEs in women from randomization until study end

• Assess safety in neonates/infants born to women randomized to receive the 2-dose Ebola vaccine regimen (Ad26.ZEBOV, MVA-BN-Filo (group A)) and in neonates/infants born to control women (unvaccinated pregnant women (group B))

• Frequency and relatedness of all SAEs in the newborns from birth until study end

• Assess the reactogenicity and unsolicited AEs of the 2-dose Ebola vaccine regimen (Ad26.ZEBOV, MVA-BN-Filo) in all vaccinated pregnant women (group A)

• Reactogenicity, defined as local and systemic solicited AEs occurring within 7 days after each dose, and unsolicited AEs within 28 days after each dose:

○ Frequency, grade, duration and causality for solicited systemic AEs and unsolicited AEs

○ Frequency, grade and duration for solicited local AEs

• Describe all pregnancy outcomes

• Pregnancy outcomes (example: normal delivery, Caesarian Section)

• Assess the immunogenicity of the 2-dose Ebola vaccine regimen (Ad26.ZEBOV, MVA-BN-Filo) in 150 pregnant women who are anticipated to receive both vaccine doses within the course of their pregnancy (a subset of the 1000 pregnant vaccinated women from group A) compared to 150 non-pregnant women vaccinated after delivery (a subset of group B)

• Anti-EBOV GP binding antibody concentrations, in ELISA units/mL (FANG ELISA) from:

○ Blood samples taken at pre-dose 1, 21 days post-dose 2, at delivery (group A subset only), and 1 year post-dose 1

○ Cord blood if feasible from women in the group A subset

• Assess persistence of maternal antibodies in 75 infants born to women from the group A subset

• Anti-EBOV GP binding antibody concentrations, in ELISA units/mL (FANG ELISA) from a blood sample taken at 14 weeks of age

Exploratory

• Assess acceptability of an Ebola vaccine among healthy pregnant women (group A)

• Description of vaccine acceptability among vaccinees after they receive both doses

• Evaluation of factors associated with study enrollment (defined as the proportion of eligible women who agree to sign the informed consent)

• Assess presence of maternal antibodies in breast milk in 50 women from group A and 10 controls (women from group B prior to vaccination)

• Evaluation of Anti-EBOV GP binding antibodies depending on availability of assays; in a sample of breast milk at 6 weeks post-delivery