A Phase 2 interventional study of JYNNEOS in Monkeypox, sponsored by National Institute of Allergy and Infectious Diseases (NIAID). Completed at 18 sites in 2 countries. Open to participants aged 12 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-27.
Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) · Phase 2, Interventional, and Prevention
This study is a Phase 2 open-label, non-placebo controlled, multi-site clinical trial that will evaluate the standard SC regimen in adolescents ages 12 through 17 years, inclusive, and compared to the standard subcutaneous regimen in adults ages 18 to 50, inclusive. Approximately 135 healthy, vaccinia-naïve adults will be enrolled in a comparator arm (Arm 4) and will be given the standard, licensed regimen of 1x10\^8 TCID50 MVA-BN administered SC on Day 1 and 29. These adults (Arm 4) will be combined with the 76 healthy, vaccinia-naïve adults that received the standard SC regimen in Stage 1 (Arm 3). Together, this will be the comparator group for non-inferiority testing for the primary endpoint. Approximately 315 healthy, vaccinia-naïve adolescents will be enrolled and given 1x10\^8 TCID50 MVA-BN administered SC on Days 1 and 29 (Arm 5). The study will have a set target enrollment of at least 25% adolescents ages 12 to 14 years, inclusive, to ensure that adequate numbers of younger adolescents are enrolled.
The primary objectives are 1.) to determine if peak (Day 43) humoral immune responses in adolescents ages 12 to 17 years following administration of a 2-dose 1 x 10\^8 TCID50 MVA-BN regimen administered SC are non-inferior to the response in adults ages 18 to 50 years who received the licensed 2-dose SC regimen of 1 x 10\^8 TCID50 MVA-BN ; and 2.) to describe safety of a 2-dose 1 x 10\^8 TCID50 MVA-BN regimen administered SC in adolescents ages 12 to 17 years.
This study is a Phase 2 open-label, non-placebo controlled, multi-site clinical trial that will evaluate to inform public health decisions regarding the use of JYNNEOS for monkey pox prevention and mitigation of outbreaks. In stage 2 of the study, the standard subcutaneous (SC) regimen in adolescents ages 12 through 17 years, inclusive, and compared to the standard SC regimen in adults ages 18 to 50, inclusive. Approximately 135 healthy, vaccinia-naïve adults will be enrolled in a comparator arm (Arm 4) and will be given the standard, licensed regimen of 1x10\^8 TCID50 MVA-BN administered SC on Day 1 and 29. These adults (Arm 4) will be combined with the 76 healthy, vaccinia-naïve adults that received the standard SC regimen in Stage 1 (Arm 3). Together, this will be the comparator group for non-inferiority testing for the primary endpoint. Approximately 315 healthy, vaccinia-naïve adolescents will be enrolled and given 1x10\^8 TCID50 MVA-BN administered SC on Days 1 and 29 (Arm 5). The study will have a set target enrollment of at least 25% adolescents ages 12 to 14 years, inclusive, to ensure that adequate numbers of younger adolescents are enrolled.
The primary objectives are 1.) to determine if peak (Day 43) humoral immune responses in adolescents ages 12 to 17 years following administration of a 2-dose 1 x 10\^8 TCID50 MVA-BN regimen administered SC are non-inferior to the response in adults ages 18 to 50 years who received the licensed 2-dose SC regimen of 1 x 108 TCID50 MVA-BN; and 2.) to describe safety of a 2-dose 1 x 10\^8 TCID50 MVA-BN regimen administered SC in adolescents ages 12 to 17 years. The secondary objectives are 1) to evaluate humoral immune responses at baseline, prior to the second vaccination, and following receipt of the 2-dose SC regimen of 1 x 10\^8 TCID50 MVA-BN in adolescents compared to adults on each study day; 2) to evaluate the kinetics of the humoral immune responses to the 2-dose SC regimen of 1 x 10\^8 TCID50 MVA-BN in adolescents and adults through Day 365 after the second dose is administered; 3.) to compare relative safety and reactogenicity between adolescent and adult study arms; and 4.) to evaluate seroconversion between adolescent and adult study arms.
72 studies on the registry are indexed under Mpox, Monkeypox; 30 are open to participants now.
This study's enrollment of 450 is above the median of 305 across 36 interventional studies indexed under Mpox, Monkeypox.
Browse Mpox, Monkeypox studies →National Institute of Allergy and Infectious Diseases (NIAID) is the lead sponsor of 2,446 studies on the registry; 179 are open to participants now.
Of its 405 completed or terminated interventional studies of FDA-regulated products, 302 (75%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Females of who have sexual intercourse with males must agree to use highly effective for at least 1 month prior to signing ICF and through Day 57.
NOTE: See MOP for definitions and list of acceptable and highly effective methods of contraception
In good general health as evidenced by medical history, physical examination, and clinical judgement of the investigator to be in stable state of health.
NOTE: Participants with pre-existing stable chronic medical conditions defined as conditions not requiring significant change in therapy or hospitalization for worsening disease in the 4 weeks prior to enrollment can be included at the discretion of the investigator. This includes stable, well-controlled positive individuals.
Exclusion Criteria:
Ever received a licensed or an smallpox or monkeypox vaccine.
*This includes Dryvax, Acam2000, LC 16 m8, MVA-based vaccine candidate or licensed vaccines, and Jynneos, Imvamune or Imvanex)
Recent or current use of any immunosuppressing medications in the 4 weeks prior to signing ICF.
**Topical, ophthalmic, inhaled, intranasal and intraarticular are acceptable, but receipt of >/=20 mg/day of prednisone or equivalent for >/=14 consecutive days in the 4 weeks prior to signing ICF is exclusionary.
Has known allergy or history of anaphylaxis or other serious adverse reaction to a vaccine or vaccine products.
***This includes individuals with history of severe allergic reaction to gentamicin, ciprofloxacin, chicken or egg protein.
Has any medical disease or condition that, in the opinion of the participating site PI or appropriate sub-investigator, precludes study participation.
****This includes acute, subacute, intermittent, or chronic medical disease or condition that would place the participant at an unacceptable risk of injury, render the participant unable to meet the requirements of the protocol, or may interfere with the evaluation of responses or the participant's successful completion of this trial.
Note: This includes positive rapid antigen test, polymerase chain reaction (PCR) assay, or other nucleic acid amplification (NAAT) test including those performed by the participant at home.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CD4 count
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
0.5 mL of 1 x 10\^8 (50% Tissue Culture Infectious Dose (TCID50) JYNNEOS (Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN)) administered subcutaneously on adults ages 18-50 years on Days 1 and 29. N=135
Biological: JYNNEOS
0.5 mL of 1 x 10\^8 (50% Tissue Culture Infectious Dose (TCID50) JYNNEOS (Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN)) administered subcutaneously on adolescents ages 12-17 years on Days 1 and 29. N=315
Biological: JYNNEOS
JYNNEOS is FDA-approved and licensed as a smallpox and monkeypox vaccine in the United States. JYNNEOS is a live vaccine produced from the strain Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN), an attenuated, non-replicating orthopoxvirus.
Vaccinia Virus Specific Plaque Reduction Neutralization Test (PRNT) Geometric Mean Titer (GMT)
Serum collected at Study Day 43 was assayed via PRNT to determine if humoral immune responses in adolescents ages 12 to 17 years are non-inferior to responses in adults after receipt of a 2-dose subcutaneous regimen of 1 x 10\^8 MVA-BN. As the primary analysis, adolescents were compared against a pooled group of adults enrolled in Stage 2 and adults enrolled in Stage 1 who received the same study product regimen. As a sensitivity analysis, adolescents were compared against only adults enrolled in Stage 2.
Time frame: Day 43
Number of Adolescents Reporting Solicited Adverse Events (AEs) by Severity
AEs solicited via memory aid provided to participants included fever, chills, nausea, headache, fatigue, change in appetite, myalgia, arthralgia, pain at the injection site, erythema/redness, induration/swelling, and pruritis at the injection site. Participants are considered reporting the AE if they reported mild or greater severity at any time through 7 days after each study vaccination (Days 1-8 for Dose 1 and Days 29-36 for Dose 2). The maximum severity reported by participants for each symptom is presented.
Time frame: Day 1 through Day 36
Number of Adolescents Reporting Unsolicited Adverse Events (AEs) by Relationship to Study Product
Frequency of all unsolicited AEs from day of each study vaccination through 28 days after each vaccination (Day 1 through Day 29 for Dose 1 and Day 29 through Day 57 for Dose 2).
Time frame: Day 1 through Day 57
Number of Adolescents Reporting Adverse Events of Special Interest (AESIs)
A protocol-specified adverse event of special interest (AESI) is defined as a case of myocarditis or pericarditis. All participants with signs and symptoms of myocarditis/pericarditis (e.g., chest pain, shortness of breath, palpitations, etc.) in whom myocarditis/pericarditis was excluded, or for whom an alternative diagnosis was made, were not be considered a suspect case and as such, not reported as an AESI. All other suspected cases of myocarditis or pericarditis were reported as an AESI and the case adjudicated using the Brighton Collaboration case definitions for myocarditis and pericarditis. The Brighton Collaboration case definitions were used to classify into possible, probable, or definite myocarditis or pericarditis cases.
Time frame: Day 1 through Day 210
Number of Adolescents Reporting Medically Attended Adverse Events (MAAEs) Related to Study Product
A medically attended adverse event (MAAE) is defined as an AE with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Adverse events identified at a routine study visit (e.g., abnormal vitals) will not be considered MAAEs.
Time frame: Day 1 through Day 210
Number of Adolescents Reporting Serious Adverse Events (SAEs) by Relatedness to Study Product
SAEs included any untoward medical occurrence that resulted in death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. All SAEs were collected from Day 1 through end of study (Day 394).
Time frame: Day 1 through Day 394
Number of Adolescents Who Withdrew From Study or Discontinued Vaccination
Participants could voluntarily withdraw their consent for study participation for any reason at any time. Primary reason for withdrawal was recorded and early termination visits were attempted. Participants who received the first vaccination could choose to discontinue receipt of study vaccine for any reason and could choose to remain in the study (i.e., not withdraw from study). In addition, a participant could be discontinued from receipt of the second vaccination. Discontinuation from vaccination did not mean automatic withdrawal from the study, and participants were monitored for safety and immunogenicity if the participant consented.
Time frame: Day 1 through Day 394
Vaccinia Virus Specific Plaque Reduction Neutralization Test (PRNT) Geometric Mean Titer (GMT)
Serum collected at Days 1, 29, 210, and 394 was assayed via PRNT to evaluate humoral immune responses in adolescents ages 12 to 17 years compared to responses in adults after receipt of a 2-dose subcutaneous regimen of 1 x 10\^8 MVA-BN.
Time frame: Days 1, 29, 210, and 394
Vaccinia Virus Specific PRNT Half-life (t ½)
Half-life, defined as the time from expected peak response (Day 43) to 50% maximal response, was estimated using the first participant visit with titer results less than or equal to half the titer results at Day 43.
Time frame: Day 1 through Day 394
Number of Participants Reporting Solicited Adverse Events (AEs) by Severity
AEs solicited via memory aid provided to participants included fever, chills, nausea, headache, fatigue, change in appetite, myalgia, arthralgia, pain at the injection site, erythema/redness, induration/swelling, and pruritis at the injection site. Participants are considered reporting the AE if they reported mild or greater severity at any time through 7 days after each study vaccination (Days 1-8 for Dose 1 and Days 29-36 for Dose 2). The maximum severity reported by participants for each symptom is presented.
Time frame: Day 1 through Day 36
Number of Participants Reporting Unsolicited Adverse Events (AEs) by Relationship to Study Product
Frequency of all unsolicited AEs from day of each study vaccination through 28 days after each vaccination (Day 1 through Day 29 for Dose 1 and Day 29 through Day 57 for Dose 2).
Time frame: Day 1 through Day 57
Number of Participants Reporting Adverse Events of Special Interest (AESIs)
A protocol-specified adverse event of special interest (AESI) is defined as a case of myocarditis or pericarditis. All participants with signs and symptoms of myocarditis/pericarditis (e.g., chest pain, shortness of breath, palpitations, etc.) in whom myocarditis/pericarditis was excluded, or for whom an alternative diagnosis was made, were not be considered a suspect case and as such, not reported as an AESI. All other suspected cases of myocarditis or pericarditis were reported as an AESI and the case adjudicated using the Brighton Collaboration case definitions for myocarditis and pericarditis. The Brighton Collaboration case definitions were used to classify into possible, probable, or definite myocarditis or pericarditis cases.
Time frame: Day 1 through Day 210
Number of Participants Reporting Medically Attended Adverse Events (MAAEs) Related to Study Product
A medically attended adverse event (MAAE) is defined as an AE with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Adverse events identified at a routine study visit (e.g., abnormal vitals) will not be considered MAAEs.
Time frame: Day 1 through Day 210
Number of Participants Reporting Serious Adverse Events (SAEs) by Relatedness to Study Product
SAEs included any untoward medical occurrence that resulted in death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. All SAEs were collected from Day 1 through end of study (Day 394).
Time frame: Day 1 through Day 394
Number of Participants Who Withdrew From Study or Discontinued Vaccination
Participants could voluntarily withdraw their consent for study participation for any reason at any time. Primary reason for withdrawal was recorded and early termination visits were attempted. Participants who received the first vaccination could choose to discontinue receipt of study vaccine for any reason and could choose to remain in the study (i.e., not withdraw from study). In addition, a participant could be discontinued from receipt of the second vaccination. Discontinuation from vaccination did not mean automatic withdrawal from the study, and participants were monitored for safety and immunogenicity if the participant consented.
Time frame: Day 1 through Day 394
Percentage of Participants With Vaccinia Virus Specific PRNT Seroconversion
Seroconversion for the Vaccinia virus specific plaque reduction neutralization test (PRNT) is defined as any positive result if negative at baseline or a 2-fold increase in antibody titers above baseline if positive at baseline. A positive result is defined as antibody titers = lower limit of detection (LLOD), i.e., a detectable result, and a negative result is defined as antibody titers \<LLOD.
Time frame: Days 29, 43, 210, and 394
Participants enrolled in 22-0020B, Stage 2, were adolescents ages 12 to 17 years, inclusive, and adults ages 18 to 50 years, inclusive, who were healthy, vaccinia-naïve, and met all eligibility criteria (N=450). They were recruited from the general population at the participating study sites. Participants were enrolled between 22MAR2023 and 20JUL2023.
| Milestone | Adolescents | Adults (Stage 2) | Adults (Stage 1) |
|---|---|---|---|
| Started | 315 | 135 | 76 |
| Completed | 308 | 125 | 71 |
| Not completed | 7 | 10 | 5 |
| Withdrew: Lost to follow-up | 5 | 9 | 2 |
| Withdrew: Withdrawal by subject | 1 | 1 | 2 |
| Withdrew: Adverse event | 1 | 0 | 0 |
| Withdrew: Protocol violation | 0 | 0 | 1 |
Serum collected at Study Day 43 was assayed via PRNT to determine if humoral immune responses in adolescents ages 12 to 17 years are non-inferior to responses in adults after receipt of a 2-dose subcutaneous regimen of 1 x 10\^8 MVA-BN. As the primary analysis, adolescents were compared against a pooled group of adults enrolled in Stage 2 and adults enrolled in Stage 1 who received the same study product regimen. As a sensitivity analysis, adolescents were compared against only adults enrolled in Stage 2.
| titer | Adolescents | Adults (Stage 2) | Pooled Adults (Stage 1 + Stage 2) |
|---|---|---|---|
| Vaccinia Virus Specific Plaque Reduction Neutralization Test (PRNT) Geometric Mean Titer (GMT) | 470.3 (422.3 to 523.8) | 295.7 (240.8 to 363.2) | 293.2 (249.8 to 344.2) |
AEs solicited via memory aid provided to participants included fever, chills, nausea, headache, fatigue, change in appetite, myalgia, arthralgia, pain at the injection site, erythema/redness, induration/swelling, and pruritis at the injection site. Participants are considered reporting the AE if they reported mild or greater severity at any time through 7 days after each study vaccination (Days 1-8 for Dose 1 and Days 29-36 for Dose 2). The maximum severity reported by participants for each symptom is presented.
| Participants | Adolescents (12-14 Years Old) | Adolescents (15-17 Years Old) |
|---|---|---|
| Mild | 154 | 138 |
| Moderate | 98 | 84 |
| Severe | 18 | 7 |
Frequency of all unsolicited AEs from day of each study vaccination through 28 days after each vaccination (Day 1 through Day 29 for Dose 1 and Day 29 through Day 57 for Dose 2).
| Participants | Adolescents (12-14 Years Old) | Adolescents (15-17 Years Old) |
|---|---|---|
| Related — Mild | 76 | 70 |
| Related — Moderate | 8 | 2 |
| Related — Severe | 0 | 0 |
| Related — None | 77 | 82 |
| Not Related — Mild | 42 | 32 |
| Not Related — Moderate | 21 | 10 |
| Not Related — Severe | 5 | 0 |
| Not Related — None | 93 | 112 |
A protocol-specified adverse event of special interest (AESI) is defined as a case of myocarditis or pericarditis. All participants with signs and symptoms of myocarditis/pericarditis (e.g., chest pain, shortness of breath, palpitations, etc.) in whom myocarditis/pericarditis was excluded, or for whom an alternative diagnosis was made, were not be considered a suspect case and as such, not reported as an AESI. All other suspected cases of myocarditis or pericarditis were reported as an AESI and the case adjudicated using the Brighton Collaboration case definitions for myocarditis and pericarditis. The Brighton Collaboration case definitions were used to classify into possible, probable, or definite myocarditis or pericarditis cases.
| Participants | Adolescents (12-14 Years Old) | Adolescents (15-17 Years Old) |
|---|---|---|
| Number of Adolescents Reporting Adverse Events of Special Interest (AESIs) | 0 | 0 |
A medically attended adverse event (MAAE) is defined as an AE with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Adverse events identified at a routine study visit (e.g., abnormal vitals) will not be considered MAAEs.
| Participants | Adolescents (12-14 Years Old) | Adolescents (15-17 Years Old) |
|---|---|---|
| Number of Adolescents Reporting Medically Attended Adverse Events (MAAEs) Related to Study Product | 0 | 0 |
SAEs included any untoward medical occurrence that resulted in death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. All SAEs were collected from Day 1 through end of study (Day 394).
| Participants | Adolescents (12-14 Years Old) | Adolescents (15-17 Years Old) |
|---|---|---|
| Related | 0 | 0 |
| Not Related | 2 | 1 |
Participants could voluntarily withdraw their consent for study participation for any reason at any time. Primary reason for withdrawal was recorded and early termination visits were attempted. Participants who received the first vaccination could choose to discontinue receipt of study vaccine for any reason and could choose to remain in the study (i.e., not withdraw from study). In addition, a participant could be discontinued from receipt of the second vaccination. Discontinuation from vaccination did not mean automatic withdrawal from the study, and participants were monitored for safety and immunogenicity if the participant consented.
| Participants | Adolescents (12-14 Years Old) | Adolescents (15-17 Years Old) |
|---|---|---|
| Withdrew from Study | 4 | 3 |
| Discontinued Vaccination | 3 | 0 |
Serum collected at Days 1, 29, 210, and 394 was assayed via PRNT to evaluate humoral immune responses in adolescents ages 12 to 17 years compared to responses in adults after receipt of a 2-dose subcutaneous regimen of 1 x 10\^8 MVA-BN.
| titer | Adolescents | Adults (Stage 2) |
|---|---|---|
| Day 1 | 10.0 (10.0 to 10.1) | 10.8 (9.9 to 11.8) |
| Day 29 | 51.1 (45.6 to 57.4) | 45.7 (36.9 to 56.7) |
| Day 210 | 43.9 (39.7 to 48.5) | 26.4 (21.8 to 32.0) |
| Day 394 | 44.8 (40.3 to 49.7) | 23.1 (19.2 to 27.8) |
Half-life, defined as the time from expected peak response (Day 43) to 50% maximal response, was estimated using the first participant visit with titer results less than or equal to half the titer results at Day 43.
| days | Adolescents | Adults (Stage 2) |
|---|---|---|
| Vaccinia Virus Specific PRNT Half-life (t ½) | 166 (136 to 370) | 167 (156 to 362) |
AEs solicited via memory aid provided to participants included fever, chills, nausea, headache, fatigue, change in appetite, myalgia, arthralgia, pain at the injection site, erythema/redness, induration/swelling, and pruritis at the injection site. Participants are considered reporting the AE if they reported mild or greater severity at any time through 7 days after each study vaccination (Days 1-8 for Dose 1 and Days 29-36 for Dose 2). The maximum severity reported by participants for each symptom is presented.
| Participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Mild | 292 | 125 |
| Moderate | 182 | 82 |
| Severe | 25 | 27 |
Frequency of all unsolicited AEs from day of each study vaccination through 28 days after each vaccination (Day 1 through Day 29 for Dose 1 and Day 29 through Day 57 for Dose 2).
| Participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Related — Mild | 146 | 85 |
| Related — Moderate | 10 | 10 |
| Related — Severe | 0 | 0 |
| Related — None | 159 | 40 |
| Not Related — Mild | 74 | 36 |
| Not Related — Moderate | 31 | 11 |
| Not Related — Severe | 5 | 3 |
| Not Related — None | 205 | 85 |
A protocol-specified adverse event of special interest (AESI) is defined as a case of myocarditis or pericarditis. All participants with signs and symptoms of myocarditis/pericarditis (e.g., chest pain, shortness of breath, palpitations, etc.) in whom myocarditis/pericarditis was excluded, or for whom an alternative diagnosis was made, were not be considered a suspect case and as such, not reported as an AESI. All other suspected cases of myocarditis or pericarditis were reported as an AESI and the case adjudicated using the Brighton Collaboration case definitions for myocarditis and pericarditis. The Brighton Collaboration case definitions were used to classify into possible, probable, or definite myocarditis or pericarditis cases.
| Participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Number of Participants Reporting Adverse Events of Special Interest (AESIs) | 0 | 0 |
A medically attended adverse event (MAAE) is defined as an AE with medically attended visits including hospital, emergency room, urgent care clinic, or other visits to or from medical personnel for any reason. Adverse events identified at a routine study visit (e.g., abnormal vitals) will not be considered MAAEs.
| Participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Number of Participants Reporting Medically Attended Adverse Events (MAAEs) Related to Study Product | 0 | 2 |
SAEs included any untoward medical occurrence that resulted in death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect. All SAEs were collected from Day 1 through end of study (Day 394).
| Participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Related | 0 | 0 |
| Not Related | 3 | 2 |
Participants could voluntarily withdraw their consent for study participation for any reason at any time. Primary reason for withdrawal was recorded and early termination visits were attempted. Participants who received the first vaccination could choose to discontinue receipt of study vaccine for any reason and could choose to remain in the study (i.e., not withdraw from study). In addition, a participant could be discontinued from receipt of the second vaccination. Discontinuation from vaccination did not mean automatic withdrawal from the study, and participants were monitored for safety and immunogenicity if the participant consented.
| Participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Withdrew from Study | 7 | 10 |
| Discontinued Vaccination | 3 | 4 |
Seroconversion for the Vaccinia virus specific plaque reduction neutralization test (PRNT) is defined as any positive result if negative at baseline or a 2-fold increase in antibody titers above baseline if positive at baseline. A positive result is defined as antibody titers = lower limit of detection (LLOD), i.e., a detectable result, and a negative result is defined as antibody titers \<LLOD.
| percentage of participants | Adolescents | Adults (Stage 2) |
|---|---|---|
| Day 29 | 82.6 (77.9 to 86.6) | 76.9 (68.8 to 83.7) |
| Day 43 | 99.0 (97.1 to 99.8) | 97.7 (93.5 to 99.5) |
| Day 210 | 82.9 (78.2 to 86.9) | 54.6 (45.7 to 63.4) |
| Day 394 | 81.5 (76.7 to 85.7) | 46.0 (37.0 to 55.1) |
Collected over Solicited events, including local and systemic AEs, were collected from the time of each study vaccination through 7 days after vaccination. Unsolicited, non-serious AEs were collected from Day 1 through Day 57. AESIs and MAAEs were collected from Day 1 through Day 210. SAEs were collected from Day 1 through end of study (Day 394).. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Adolescents | 0/315 (0%) | 3/315 (1%) | 301/315 (95.6%) |
| Adults (Stage 2) | 0/135 (0%) | 2/135 (1.5%) | 128/135 (94.8%) |
| Event | Adolescents | Adults (Stage 2) |
|---|---|---|
| PyelonephritisInfections and infestations | 1/315 | 1/135 |
| Suicidal ideationPsychiatric disorders | 0/315 | 1/135 |
| Major depressionPsychiatric disorders | 1/315 | 0/135 |
| Infective myositisInfections and infestations | 1/315 | 0/135 |
| Event | Adolescents | Adults (Stage 2) |
|---|---|---|
| Injection Site PainGeneral disorders | 232/315 | 103/135 |
| Injection Site ErythemaGeneral disorders | 192/315 | 100/135 |
| Injection Site IndurationGeneral disorders | 175/315 | 90/135 |
| Injection Site PruritusGeneral disorders | 158/315 | 81/135 |
| Injection Site NoduleGeneral disorders | 117/315 | 79/135 |
| FatigueGeneral disorders | 164/315 | 66/135 |
| HeadacheNervous system disorders | 157/315 | 60/135 |
| MyalgiaMusculoskeletal and connective tissue disorders | 129/315 | 47/135 |
| Injection Site DiscolourationGeneral disorders | 53/315 | 38/135 |
| NauseaGastrointestinal disorders | 75/315 | 20/135 |
| Age, Continuous(years) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| Mean | 14.4 ± 1.7 | 36.1 ± 9.1 | 32.7 ± 9.1 | 22.6 ± 11.7 |
| Age, Customized(Participants) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| 12-14 years | 161 | 0 | 0 | 161 |
| 15-17 years | 154 | 0 | 0 | 154 |
| 18 years and older | 0 | 135 | 76 | 211 |
| Sex: Female, Male(Participants) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| Female | 155 | 80 | 37 | 272 |
| Male | 160 | 55 | 39 | 254 |
| Ethnicity (NIH/OMB)(Participants) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| Hispanic or Latino | 63 | 40 | 22 | 125 |
| Not Hispanic or Latino | 251 | 95 | 54 | 400 |
| Unknown or Not Reported | 1 | 0 | 0 | 1 |
| Race (NIH/OMB)(Participants) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 1 | 1 |
| Asian | 8 | 5 | 7 | 20 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 | 0 |
| Black or African American | 31 | 17 | 14 | 62 |
| White | 216 | 98 | 47 | 361 |
| More than one race | 57 | 13 | 4 | 74 |
| Unknown or Not Reported | 3 | 2 | 3 | 8 |
| Region of Enrollment(Participants) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| United States | 315 | 135 | 76 | 526 |
| HIV Status(Participants) | Adolescents | Adults (Stage 2) | Adults (Stage 1) | Total |
|---|---|---|---|---|
| Negative | 314 | 133 | 73 | 520 |
| Positive | 1 | 2 | 3 | 6 |
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Studies of the drug tested here: MVA-BN smallpox vaccine
National Institute of Allergy and Infectious Diseases (NIAID) →