JYNNEOS Vaccine for Monkeypox

No longer recruiting at 50 trial locations

Overseen By 22-0020 Central Contact

Age: < 65

Sex: Any

Trial Phase: Phase 2

Sponsor: National Institute of Allergy and Infectious Diseases (NIAID)

Must be taking: Suppressive ART

Must not be taking: Immunosuppressants, Prednisone

Disqualifiers: Smallpox vaccine, Monkeypox history, Immunocompromised, Pregnancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 2

Duration: 4 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests the JYNNEOS vaccine to determine its effectiveness and safety for adolescents aged 12 to 17 compared to adults aged 18 to 50. Researchers aim to compare the immune response (how the body defends itself) after vaccination between these two groups. The trial seeks healthy individuals who have never received a smallpox or monkeypox vaccine. Those with stable chronic conditions, such as controlled HIV, might still qualify. As a Phase 2 trial, this research focuses on measuring the treatment's effectiveness in an initial, smaller group of participants.

Do I have to stop taking my current medications to join the trial?

The trial does not specify if you need to stop taking your current medications. However, if you are using immunosuppressing medications or high doses of certain steroids, you may not be eligible. It's best to discuss your specific medications with the trial team.

Is there any evidence suggesting that this treatment is likely to be safe for humans?

Research has shown that the JYNNEOS vaccine was well-tolerated in past studies. This vaccine, used for smallpox and monkeypox, does not contain a virus that can grow in humans, reducing the risk of illness from the vaccine itself. Real-world data from its widespread use confirms its safety when administered as a shot under the skin.

In these studies, most side effects were mild, such as redness, swelling, or pain at the injection site. Other common effects included fatigue or headache, typical for vaccines. Serious side effects were rare. The JYNNEOS vaccine is already approved for adults, indicating its safety. This trial will help confirm its safety in teenagers. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for monkeypox?

Researchers are excited about the JYNNEOS vaccine for monkeypox because it uses a non-replicating modified vaccinia virus, known as Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN), which is designed to be safer for a wider range of people, including those with weakened immune systems. Unlike some existing smallpox vaccines, which can have significant side effects, JYNNEOS is administered subcutaneously and is generally well-tolerated. This vaccine is being tested in both adults and adolescents, aiming to provide broader protection across different age groups without the risks associated with live, replicating viruses.

What evidence suggests that the JYNNEOS vaccine is effective for monkeypox?

Research has shown that the JYNNEOS vaccine helps prevent mpox (monkeypox). This trial will evaluate the vaccine in two groups: adults ages 18-50 and adolescents ages 12-17. Studies have found that two doses of the vaccine offer better protection than one dose. Specifically, one study showed that two doses were 66% effective in preventing infection. Another study found that one dose was 58% effective, but two doses are recommended for stronger protection. Overall, the JYNNEOS vaccine is a proven method to prevent mpox, especially for those at high risk. ^{6 7 8 9 10}

Are You a Good Fit for This Trial?

This trial is for healthy adults aged 18-50 and adolescents 12-17 who have never had a smallpox or monkeypox vaccine, no history of certain pox infections, not immunocompromised, and not on recent immunosuppressing meds. Women must agree to use effective contraception. Participants with stable chronic conditions including well-controlled HIV can join.

Inclusion Criteria

I can read and agree to follow the study's procedures and attend all visits.

I have HIV, on ART for 6+ months, CD4 count >350, no AIDS illness last year.

In good general health as evidenced by medical history, physical examination, and clinical judgement of the investigator to be in stable state of health.

Exclusion Criteria

You have a heart condition that makes participating in the study risky, such as a history of inflammation of the heart or a structural heart defect.

I have received a smallpox vaccine.

Any history of monkeypox, cowpox, or vaccinia infection.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive a 2-dose 1 x 10^8 TCID50 MVA-BN regimen administered subcutaneously on Days 1 and 29

4 weeks

2 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

52 weeks

What Are the Treatments Tested in This Trial?

Interventions

• JYNNEOS

Trial Overview The study tests two different dosages of the MVA-BN vaccine given intradermally (ID) against the standard dose given subcutaneously (SC) in adults. It aims to see if the immune response with lower ID doses is just as good as the standard SC dose. Adolescents will receive the standard SC regimen for comparison.

How Is the Trial Designed?

Group I: 5 Experimental Treatment 1 Intervention

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

Group II: 4 Active Control 1 Intervention

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

Who Is Running the Clinical Trial?

National Institute of Allergy and Infectious Diseases (NIAID)

Lead Sponsor

Trials

3,361

Recruited

5,516,000+

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/39260880/

Effectiveness of modified vaccinia Ankara-Bavarian Nordic ... Estimated vaccine effectiveness of one dose of MVA-BN against mpox infection was 58% (95% CI 31% to 75%). Conclusion: The findings of this study ...

2. nejm.org nejm.org/doi/full/10.1056/NEJMoa2215201

Vaccine Effectiveness of JYNNEOS against Mpox Disease ... The findings suggest that JYNNEOS vaccine was effective in preventing mpox disease, and a two-dose series appeared to provide better protection.

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10874271/

Effectiveness of Modified Vaccinia Ankara-Bavaria Nordic ... These results confirm that MVA-BN vaccination is an effective prevention tool in a population at high risk of MPXV infection, at least shortly after vaccine ...

4. jamanetwork.com jamanetwork.com/journals/jama/fullarticle/2824688

Decline of Mpox Antibody Responses After Modified ... Two doses of MVA-BN are recommended, although some individuals received only 1 dose. Two doses provided 66% effectiveness and 1 dose provided 36 ...

5. sciencedirect.com sciencedirect.com/science/article/pii/S0264410X24010910

MVA-BN vaccine effectiveness: A systematic review of real- ... The reported VE estimates against mpox infection demonstrated the effectiveness of one or two doses of MVA-BN in the context of an outbreak across multiple ...

6. fda.gov fda.gov/media/131078/download

Package Insert - JYNNEOS (Refrigerator) The safety of JYNNEOS one-vial presentation in smallpox vaccine-naïve participants was evaluated in Study 1 [1], a randomized, double-blind, placebo-controlled ...

7. who.int who.int/publications/i/item/B09202

MVA-BN (‎Modified Vaccinia Ankara – Bavarian Nordic)‎ ... The MVA-BN (live Modified Vaccinia Ankara) vaccine is a third-generation smallpox vaccine, which contains a virus that cannot replicate in humans.

8. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0264410X24006510

Real-world safety data for MVA-BN: Increased frequency of ... Real-world data from large-scale administration of MVA-BN has confirmed the vaccine's established safety profile when administered subcutaneously.

9. thelancet.com thelancet.com/journals/laninf/article/PIIS1473-3099(25)00018-0/fulltext

Safety and effectiveness of MVA-BN vaccination against ... The third-generation smallpox vaccine modified vaccinia Ankara–Bavarian Nordic (MVA-BN) was recommended for at-risk populations in 2022, despite ...

10. niaid.nih.gov niaid.nih.gov/diseases-conditions/mpox-vaccines

Mpox Vaccines | NIAID Researchers found that that the immune responses induced by the JYNNEOS vaccine or the ACAM2000 smallpox vaccine were not significantly affected ...