An AE can be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of study vaccine or protocol-specified procedure, whether or not considered related to the study vaccine or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the study vaccine or protocol-specified procedure is also an adverse event. Injection-site AEs prompted on the Vaccination Report Card (VRC) were erythema, pain, tenderness and swelling. AEs were assessed for severity by the investigator according to a toxicity grading scale based on the FDA Guidance for Industry: Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials. Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening. The percentage of participants that experienced at least 1 solicited injection-site AE was summarized by grade.

An AE can be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of study vaccine or protocol-specified procedure, whether or not considered related to the study vaccine or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the study vaccine or protocol-specified procedure is also an adverse event. Systemic AEs included subjective and objective fever, shivering/chills, sweats, myalgia, arthralgia, joint swelling, joint tenderness, fatigue, headache, gastrointestinal symptoms (nausea, vomiting, abdominal pain, and diarrhea), mucosal lesion, and skin lesion (including any blisters). AEs were assessed for severity by the investigator as follows: Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening. The percentage of participants that experienced at least one systemic AE was summarized by grade.

An AE can be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of study vaccine or protocol-specified procedure, whether or not considered related to the study vaccine or protocol-specified procedure. Any worsening of a preexisting condition that is temporally associated with the use of the study vaccine or protocol-specified procedure is also an adverse event. Unsolicited vaccine-related AEs were those events not specifically listed as either an injection-site (local) or systemic in the VRC and were reported as at least possibly related to the study vaccine or placebo. The AEs were further assessed for severity by the investigator as follows: Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening. The percentage of participants that experienced at least one unsolicited vaccine-related AE was summarized by grade..

An adverse event is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. An SAE is an AE that results in death, is life-threatening, results in a persistent or significant disability or incapacity, results in or prolongs an existing hospitalization, is a congenital anomaly or birth defect, or is another important medical event. SAEs were assessed for severity by the investigator as follows: Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening; 5=Fatal. The percentage of participants that experienced at least 1 SAE was summarized by grade.

Blood was drawn on Day 28 to assess the GMTs of ZEBOV-specific IgG antibodies as determined by Enzyme-linked immunosorbent assay (ELISA).

The optimum dose for general use prophylaxis with V920 was determined following the review of all immunogenicity and safety data.

An adverse event (AE) is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A treatment-emergent adverse event (TEAE) is defined as an AE that starts or worsens on or after the date and time of the study vaccination. Local reactogenicity signs and symptoms include pain, erythema (redness), and induration (swelling). The number of participants that experienced at least one solicited local TEAE was assessed. Solicited TEAEs occurred from the time of each injection through 14 days following the procedure, facilitated with the use of a memory aid to record participant observations.

An AE is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A TEAE is defined as an AE that starts or worsens on or after the date and time of the study vaccination. Local reactogenicity signs and symptoms include pain, erythema (redness), and induration (swelling). AEs were assessed for severity by the investigator according to a toxicity grading scale based on the FDA's Guidance for Industry "Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials": Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening. The number of participants that experienced at least one solicited local TEAE was summarized by grade. Solicited TEAEs occurred from the time of each injection through 14 days following the procedure, facilitated with the use of a memory aid to record participant observations.

An adverse event (AE) is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A treatment-emergent adverse event is defined as an AE that starts or worsens on or after the date and time of the study vaccination. Systemic reactogenicity signs and symptoms include pyrexia (subjective and objective fever), chills, hyperhidrosis (sweats), myalgia, arthralgia, fatigue, headache, and gastrointestinal symptoms including nausea, vomiting, abdominal pain, and/or diarrhea. The number of participants that experienced at least one solicited systemic TEAE was assessed. Solicited TEAEs occurred from the time of each injection through 14 days following the procedure, facilitated with the use of a memory aid to record participant observations.

An AE is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A TEAE is defined as an AE that starts or worsens on or after the date and time of the study vaccination. Systemic reactogenicity signs and symptoms include pyrexia (subjective and objective fever), chills, hyperhidrosis (sweats), myalgia, arthralgia, fatigue, headache, and gastrointestinal symptoms including nausea, vomiting, abdominal pain, and/or diarrhea. AEs were assessed for severity by the investigator as follows: Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening. The number of participants that experienced at least 1 solicited systemic TEAE was summarized by grade. Solicited TEAEs occurred from the time of each injection through 14 days following the procedure, facilitated with the use of a memory aid to record participant observations.

An adverse event (AE) is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A treatment-emergent adverse event is defined as an AE that starts or worsens on or after the date and time of the study vaccination. The number of participants that experienced at least one unsolicited TEAE was assessed. Unsolicited AEs occurred from the time of injection through 28 days following injection.

An adverse event (AE) is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A treatment-emergent adverse event is defined as an AE that starts or worsens on or after the date and time of the study vaccination. A related TEAE is defined as a TEAE that was possibly, probably, or definitely related to the vaccination as assessed by the investigator. The number of participants that experienced at least one unsolicited TEAE related to study vaccination was assessed.

An adverse event (AE) is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A treatment-emergent adverse event is defined as an AE that starts or worsens on or after the date and time of the study vaccination. A related TEAE is defined as a TEAE that was possibly, probably, or definitely related to the vaccination as assessed by the investigator. AEs were assessed for severity by the investigator according to a toxicity grading scale based on the FDA's Guidance for Industry "Toxicity Grading Scale for Healthy Adult and Adolescent Volunteers Enrolled in Preventive Vaccine Clinical Trials": Grade 1=Mild; Grade 2=Moderate; Grade 3=Severe; Grade 4=Potentially life-threatening. The number of participants that experienced at least one unsolicited TEAE related to study vaccination was summarized by grade.

An adverse event (AE) is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. The number of participants prematurely withdrawing from the study due to an AE was assessed.

An adverse event is defined as any untoward medical occurrence in a participant which does not necessarily have a causal relationship with study vaccine. A serious adverse event (SAE) is an AE that results in death, is life-threatening, results in a persistent or significant disability or incapacity, results in or prolongs an existing hospitalization, is a congenital anomaly or birth defect, or is another important medical event. The number of participants that experienced one or more SAE was summarized.