OUTCOMES |
Type of outcome
|
Outcome
|
Timepoint(s) at which outcome measured
|
Primary Outcome |
Separately for adults and children: To compare each of the three vaccine strategies with the matched placebo group (3 pair-wise comparisons) for antibody response 12 months after randomization (prime vaccination).
In order to facilitate Merck regulatory filings and bridging of immune responses of the rVSVΔG-ZEBOV-GP vaccine from this study to other studies and between pediatric and adult populations, the following objective will be assessed specifically for those in the two rVSVΔG-ZEBOV-GP vaccine groups:
• To compare the rVSVΔG-ZEBOV-GP vaccine (pooled rVSVΔG-ZEBOV-GP groups) with the matched placebo group for antibody response 28 days after randomization (prime vaccination).
In order to facilitate Janssen regulatory filings of the rHAd26/MVA vaccine, the following objective will be assessed specifically for those in the rHAd26/MVA vaccine group:
• To compare the rHAd26/MVA vaccine group with the matched placebo group for antibody response 3 months after randomization (approximately 28 days after the booster vaccination).
|
12 Months |
Secondary Outcome |
Addressed separately for adults and children: To compare the groups given the Ad26.ZEBOV prime vaccine and the rVSVΔG-ZEBOV-GP prime vaccine (both rVSVΔG-ZEBOV-GP groups combined) each with the pooled placebo group for the antibody response 14 days after randomization (prime vaccination) (immediacy of response). |
14 days |
Secondary Outcome |
Addressed separately for adults and children:
To compare each of the vaccine groups versus the pooled placebo group for the antibody response profile using measurements at 7, 14, 28, 56, 63 days and at 3, 6 and 12 months after randomization
|
12 months |
Secondary Outcome |
Addressed separately for adults and children:
• To compare each of the vaccine groups with the pooled placebo group for SAEs at 12 months |
12 months |
Secondary Outcome |
Addressed separately for adults and children:
• To compare the groups given the Ad26.ZEBOV prime vaccine and the rVSVΔG-ZEBOV-GP prime vaccine (both rVSVΔG-ZEBOV-GP groups combined) each with the pooled placebo group for the percent with injection site reactions and AEs graded for severity, including targeted symptoms, during the first week following randomization (including the daily contacts for children only).
|
1 week |
Secondary Outcome |
• To compare each of the vaccine groups with the pooled placebo group for changes from baseline in biochemical markers and complete blood count (CBC) measurements at 7 days after randomization (children only). |
7 days |
Secondary Outcome |
• To compare the rHAd26/MVA and rVSVΔG-ZEBOV-GP boost strategies with the pooled placebo group for changes from baseline in biochemical markers and CBC measurements at 63 days after randomization (children only). |
63 days |
Secondary Outcome |
Addressed separately for adults and children:
• To compare the rHAd26/MVA and rVSVΔG-ZEBOV-GP boost strategies with the pooled placebo for percent with injection site reactions and AEs graded for severity, including targeted symptoms, immediately following the booster vaccination and through month 3 (approximately 35 days after the booster vaccination).
|
3 months |
Secondary Outcome |
Addressed separately for adults and children:
• To compare the 3 vaccine strategies versus the pooled placebo group for long-term antibody response at 24, 36, 48 and 60 months following randomization.
|
60 months |
Secondary Outcome |
Addressed separately for adults and children:
• To compare the long-term safety at month 24, 36, 48 and 60 following the three vaccine strategies with the pooled placebo group.
|
60 months |
Secondary Outcome |
Addressed separately for adults and children:
• To compare antibody responses and safety outcomes of each of the vaccination strategies versus the pooled placebo group in subgroups defined by age, gender, country, whether the volunteer is a close contact of an Ebola case, the presence of laboratory abnormalities at baseline, and has specific co-morbidities (in particular HIV and nutritional status as measured by body mass index).
|
60 months |
Secondary Outcome |
For adults and children combined, to compare antibody responses and safety outcomes for each of the vaccination strategies versus placebo.
• To carry out operational research which will include ethnographic, participatory and/or qualitative (i.e., focus groups and individual interviews) studies to: 1) identify issues relevant to understanding and acceptability of the trial, the social issues surrounding informed consent, with the primary goal of informing efforts to ensure autonomous fully informed individual consent and assent for minors; 2) describe participants' and caregivers' experience in the trial, and identify barriers and develop solutions to support
trial adherence in a culturally sensitive and ethically appropriate way; and 3) understand prevailing representations and affects surrounding the epidemic (including rumors), Ebola and other vaccines, the trial and other relevant phenomena in order to ensure effective communication around the
trial. No specific timepoints; they will be developed and implemented throughout the study |
0 |
Secondary Outcome |
Addressed separately for adults and children:
• In a subsample of adults in Guinea, T cell and memory B cell responses for the three vaccine strategies versus placebo will be compared (see Appendix D).
|
Day 14 Day 70 Months 12, 24, 36, 48, 60 |
Secondary Outcome |
In a subsample of children, to compare the rVSVΔG-ZEBOV-GP vaccine strategies with the pooled placebo group for shedding of rVSV-ZEBOV-GP RNA, See Appendix E |
Day 7, 14,28, 56, 63, 3 months |
Secondary Outcome |
Addressed separately for adults and children:
• To determine whether exposure to malaria and helminth infections influences the durability of the humoral and cellular immune responses to Ebola vaccines (see Appendix F).
|
Day 0, Months 12, 24, 36,48, 60 |
Secondary Outcome |
Addressed separately for adults and children:
• To identify multilevel facilitators and barriers to participant retention in PREVAC through retrospective qualitative research with participants after the conclusion of the blinded trial period (first 12 months) (see Appendix G).
|
Month 12 |
Secondary Outcome |
Addressed separately for adults and children:
• To identify factors that predict participant retention and loss-to-follow-up (LTFU) during the unblinded PREVAC long-term follow-up period (from 12 months up to 5 years) through prospective research (see Appendix G).
|
Months 12, 24,36, 48, 60 |
Secondary Outcome |
Addressed separately for adults and children:
• To analyze the early vaccine signature, identify early correlates of durable antibody responses and propose in silico methods to optimally allocate vaccine strategies at the individual level.
|
Day 28 |
Secondary Outcome |
Addressed separately for adults and children: To compare the groups given the Ad26.ZEBOV prime vaccine and the rVSVΔG-ZEBOV-GP prime vaccine (both rVSVΔG-ZEBOV-GP groups combined) each with the pooled placebo group for percent reporting injection site reactions and AEs graded for severity, including targeted symptoms, following prime vaccination at the vaccination visit, and through 7, 14, and 28 days after the prime vaccination. |
28 days |