Mpox vaccine gets a production upgrade: new cell recipe under trial

NCT ID NCT07199569

What the study statuses mean

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Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing This study
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study tests whether the MVA-BN mpox vaccine (Jynneos) works as well when made in quail cells instead of chicken cells. About 970 healthy adults aged 18 to 49 will receive two doses four weeks apart. Researchers will compare immune responses and side effects between the two versions.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance
MVA-BN vaccine (Jynneos)
What this could lead to
If successful, this could confirm that the vaccine works just as well when made in quail cells, making production more flexible and reliable.
What could go wrong
This is a mid-stage trial comparing manufacturing methods, not testing a new vaccine. It may not show a clear difference, and results may not apply to older adults or those with health issues.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2

Tests whether the treatment actually works, and watches for side effects, in a larger group.

Participants

970 people

The number who actually took part.

Started

Oct 2025

Expected to finish

Nov 2026

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 49 years

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. 18 to 49 years of age 2. Informed consent form (ICF) signed and dated by the participant after reading the form and being advised of the risks and benefits of the trial in a language understood by the participant and before performance of any trial-specific procedures 3. General good health, without clinically relevant medical illness, physical exam findings, or laboratory abnormalities, as determined by the investigator that would interfere with the trial 4. Body mass index (BMI) ≥18.5 and ≤35 (calculated as \[body weight in kg\]/\[body height in m\]2 ) 5. Agreement by female participants of childbearing potential and male participants who are sexually active with a female partner of childbearing potential to use a highly effective method of birth control from at least 30 days prior to administration of the MVA-BN vaccine until 30 days after last vaccination 1. Medically acceptable methods of contraception that may be used by the participant and/or partner include combined (estrogen- and progestogen-containing) hormonal contraception associated with inhibition of ovulation (oral, intravaginal, transdermal), progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable), intrauterine device (IUD), intrauterine hormone-releasing system (IUS), combined use of 2 barrier birth control methods (male condom with female diaphragm, male condom with cervical cap), bilateral tubal occlusion, vasectomy, or abstinence (acceptable only if refraining from heterosexual intercourse during the entire period of 30 days prior to administration of the MVA-BN vaccine until 30 days after last vaccination 2. Female participants or partners are not considered to be of childbearing potential if they are at least 1 year postmenopausal Exclusion Criteria: 1. Pregnancy or breastfeeding 2. Acute or chronic condition that, in the opinion of the investigator, would render the trial procedures unsafe or would interfere with the evaluation of responses including, but not limited to, neurologic, cardiovascular, respiratory, hepatic, hematologic, rheumatologic, endocrine, gastrointestinal, renal, autoimmune, or immunosuppressive conditions 3. History of or active autoimmune disease (vitiligo or thyroid disease requiring thyroid replacement are not exclusions), history of Guillain-Barré syndrome or Reye's syndrome 4. Known immunodeficiency syndrome or known or suspected impairment of immunologic functions including, but not limited to, clinically significant liver disease, diabetes mellitus type I, or moderate to severe kidney impairment; HIV infection under stable HAART regimen (no change within the last 3 months) and CD4 count is \>500/µL is not considered immunodeficient 5. Known or reported previous smallpox vaccination or vaccination with any licensed or investigational poxvirus-based vaccine 6. History of monkeypox, cowpox, or vaccinia infection 7. Close contact in the 3 weeks prior to signing the ICF with anyone known to have mpox 8. History of malignancy other than squamous cell or basal cell skin cancer, unless there has been surgical excision at least 6 months prior to screening that is considered to have achieved cure 9. Clinically significant mental disorder not adequately controlled by medical treatment 10. Active or recent (within 6 months before screening) chronic alcohol abuse and/or intravenous and/or nasal drug abuse 11. History of allergic disease or reactions likely to be exacerbated by any component of the vaccine, eg, tris(hydroxymethyl)-amino methane, including history of allergic asthma 12. Known allergy to aminoglycosides or quinolones 13. History of anaphylaxis or severe allergic reaction to any vaccine 14. Receipt of or plans to receive any licensed live vaccine from 30 days prior to the trial vaccination until 30 days after last trial vaccination 15. Receipt of or plans to receive any licensed nonlive vaccine from 14 days prior to the trial vaccination until 14 days after last trial vaccination 16. Use of any investigational or nonregistered agent within 30 days prior to vaccination or plans to receive an investigational agent during the trial 17. Recent blood donation (including platelets, plasma, and red blood cells) within 4 weeks prior to screening, or planned blood donations during the active trial period 18. Chronic systemic administration (defined as more than 14 days) of \>5 mg prednisone (or equivalent)/day or any other immune-modifying drugs from 3 months prior to the first trial vaccination to the visit at the end of the active trial period (use of topical, inhaled, ophthalmic, and nasal glucocorticoids is allowed) 19. History of organ transplantation whether or not chronic immunosuppressive therapy is being administered 20. Abnormal troponin I level \>upper limit of normal (ULN) 21. Administration or planned administration of immunoglobulins and/or any blood products from 3 months prior to the first trial vaccination until the visit at the end of the active trial period (packed red blood cells given for an emergency indication in an otherwise healthy person and not required as ongoing treatment is not exclusionary \[eg, packed red blood cells given in an emergency during elective surgery\]) 22. History of coronary heart disease, myocardial infarction, angina, congestive heart failure, cardiomyopathy, stroke or transient ischemic attack, uncontrolled high blood pressure, significant arrhythmia with or without corrective/ablative surgery, or any other heart condition under the care of a doctor 23. Employment with the investigator or trial site, with direct involvement in the proposed trial or other studies under the direction of that investigator or trial site, or relationship to the investigator or trial site employee 24. Relationship with Bavarian Nordic as an employee or employee family member, contractor, agent, or business partner or a financial interest in the outcome of the trial

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Accellacare - Knoxville

    Knoxville, Tennessee, 37938, United States

  • Accellacare Research of Salisbury

    Salisbury, North Carolina, 28144, United States

  • Accellacare and McFarland Clinic

    Ames, Iowa, 50010, United States

  • Accellacare of Cary - Cary Medical Group

    Cary, North Carolina, 27518, United States

  • Accellacare of Charleston

    Mt. Pleasant, South Carolina, 29464, United States

  • Avacare

    Austin, Texas, 78705, United States

  • Avacare

    Fort Worth, Texas, 76135, United States

  • Johnson County ClinTrials, LLC

    Lenexa, Kansas, 66219, United States

  • Rochester Clinical Research, Inc

    Rochester, New York, 14609, United States

  • Velocity Clinical Research

    Suffolk, Virginia, 23435, United States

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Other studies related to the condition(s) this trial covers.