JYNNEOS Smallpox Vaccine in Adult Healthcare Personnel at Risk for Mpox in the Democratic Republic of the Congo

NCT02977715 | Completed Phase 3 FDA Drug

• 1 other identifier: CDC-IRB-6859
• Study Type: interventional
• Target: 1,600
• Locations: 1 country
• Sites: 1

Brief Summary

Mpox is a febrile rash illness caused by the monkeypox virus. Its natural occurrence in the DRC puts healthcare and frontline workers at high risk of acquiring monkeypox virus infections that can prevent them from performing work duties, compromise the overall healthcare delivery in an already fragile system, and can result in death (case fatality estimates are approximately 10%). This is an open-label prospective cohort study in up to 1,600 eligible healthcare workers at risk of mpox infection through their daily work. The study will document mpox exposure and infection in participants while concurrently evaluating the immunogenicity and safety of the vaccine, JYNNEOS (also known as MVA-BN, IMVAMUNE®, IMVANEX), in healthcare personnel in the DRC. Participation in the study is voluntary and open to male and female healthcare personnel ages 18 years and older in Tshuapa Province in The Democratic Republic of Congo who are at risk of monkeypox virus infection through their daily work or laboratory personnel performing diagnostic testing for monkeypox virus.

Conditions

Monkeypox Virus Infection

Keywords

Democratic Republic of the Congo; Modified Vaccinia Ankara (MVA); Monkeypox; Orthopoxvirus; Vaccine; Vaccinia virus; JYNNEOS; Mpox

Outcome Measures

Primary Outcomes (5)

• Monkeypox virus infection

  Proportion of participants who develop suspected or confirmed monkeypox virus infection following receipt of JYNNEOS

  2 years following initial vaccination

• Monkeypox virus exposure

  Proportion of participants who experience exposure to monkeypox virus following receipt of JYNNEOS

  2 years following initial vaccination

• Orthopoxvirus Antibody Response

  Proportion of participants who have orthopoxvirus antibody responses

  Days 0, 14, 28, 42, 180, 365, 545, and 730 days after the receipt of the first dose of vaccine; Days 3, 7, and/or 14, and through study completion (an average of 1 year) after receipt of single booster dose of vaccine.

• Distribution of Geometric Means Titers (GMTs)

  Distribution of geometric means titers (GMTs)

  Days 0, 14, 28, 42, 180, 365, 545, and 730 days after the receipt of the first dose of vaccine; Days 3, 7, and/or 14, and through study completion (an average of 1 year) after receipt of single booster dose of vaccine.

• Adverse event and serious adverse event information

  Number of participants with reported local or systemic vaccine-associated adverse events by dose, including Serious Adverse Events and Deaths

  2 years following initial vaccination; Day 3, 7, and/or 14 after receipt of single booster dose of vaccine

Study Arms (3)

Intervention (Liquid Formulation)

EXPERIMENTAL

Up to 1000 male and female healthcare personnel ages 18 years and older in Tshuapa Province in The Democratic Republic of Congo at risk for mpox will receive two doses of attenuated live virus smallpox vaccine (JYNNEOS liquid formulation) administered on days 0 and 28 via subcutaneous injection (deltoid) (1 x 10\^8 Tissue Culture Infectious Dose 50 \[TCID50\] per 0.5 mL). A subset of participants will receive a booster dose.

Biological: JYNNEOS (Liquid Formulation)

Intervention (Lyophilized Formulation)

EXPERIMENTAL

Up to 600 male and female healthcare personnel ages 18 years and older in Tshuapa Province in The Democratic Republic of Congo at risk for mpox will receive two doses of attenuated live virus smallpox vaccine (JYNNEOS lyophilized formulation) administered on days 0 and 28 via subcutaneous injection (deltoid) (1 x 10\^8 Tissue Culture Infectious Dose 50 \[TCID50\] per 0.5 mL). A subset of participants will receive a booster dose.

Biological: JYNNEOS (Lyophilized Formulation)

Single booster dose (Liquid Formulation)

EXPERIMENTAL

Up to 400 male and female healthcare personnel ages 18 years and older who received primary vaccination as a previous study participant

Biological: JYNNEOS (Liquid Formulation)

Interventions

JYNNEOS (Liquid Formulation) BIOLOGICAL

Two doses of attenuated live virus smallpox vaccine (JYNNEOS liquid formulation) administered on days 0 and 28 via subcutaneous injection (deltoid) (1 x 10\^8 Tissue Culture Infectious Dose 50 \[TCID50\] per 0.5 mL). A subset of participants will receive a booster dose.

Also known as: Modified Vaccinia Ankara (MVA), MVA-BN, IMVAMUNE, IMVANEX

Intervention (Liquid Formulation); Single booster dose (Liquid Formulation)

JYNNEOS (Lyophilized Formulation) BIOLOGICAL

Two doses of attenuated live virus smallpox vaccine (JYNNEOS lyophilized formulation) administered on days 0 and 28 via subcutaneous injection (deltoid) (1 x 10\^8 Tissue Culture Infectious Dose 50 \[TCID50\] per 0.5 mL). A subset of participants will receive a booster dose.

Also known as: Modified Vaccinia Ankara (MVA), MVA-BN, IMVAMUNE, IMVANEX

Intervention (Lyophilized Formulation)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Males and nonpregnant females (as indicated by a negative urine pregnancy test prior to first dose of vaccine) age 18 years and older.
• Healthcare personnel at risk of mpox infection working in the Tshuapa Province of DRC or laboratory personnel performing diagnostic testing for mpox at the time of enrollment
• Willing to adhere to infection control recommendations to the extent possible based on availability of resources.
• Able and willing to complete the informed consent process and study procedures (including blood sample collection, urine pregnancy test, and completion of adverse event diary and exposure forms).
• Available for all study visits.

You may not qualify if:

• Any history of allergy or anaphylaxis to any prior vaccines, eggs, or aminoglycosides.
• Current pregnancy (a negative urine pregnancy test is required for women participants who self-report as not pregnant). Enrollment for such participants may be deferred to a later time at which this criteria can be met.
• Acute illness that is accompanied by an axillary temperature ≥37.2°C (99.0°F) at the time of vaccination. Enrollment for such participants may be deferred to a later time at which this criteria can be met.
• Known experimental research agents or other vaccine within 28 days (4 weeks) prior to vaccination. Enrollment for such participants may be deferred to a later time at which this criteria can be met.
• Any reason the PIs suspect that data collected from this person would be incomplete or of poor quality.
• Any condition that the PIs suspect may place the participant at an unacceptable risk of injury or render the participant unable to meet the requirements of the protocol.

Sponsors & Collaborators

• Centers for Disease Control and Prevention: lead
• Ministry of Public Health, Democratic Republic of the Congo: collaborator
• Kinshasa School of Public Health: collaborator
• Bavarian Nordic: collaborator

Study Sites (1)

Tshuapa site

Boende, Tshuapa, Democratic Republic of the Congo

Location

Related Publications (4)

• Priyamvada L, Minhaj FS, Likafi T, Pukuta E, Muyamuna E, Carson WC, Moriarty M, Rodriguez S, Joseph T, Kabamba J, Kokola G, Lushima RS, Muyembe-Tamfum JJ, Hughes CM, Petersen BW, Yu Y, Rao A, McCollum AM, Kaba DK, Nguete BU, Satheshkumar PS, Townsend MB. Immunogenicity and safety of MVA-BN vaccine administered 5 years after a two-dose primary series in DR Congo: a prospective cohort study. Lancet Infect Dis. 2026 Mar 9:S1473-3099(26)00001-0. doi: 10.1016/S1473-3099(26)00001-0. Online ahead of print.

  PMID: 41819114 RESULT

• Minhaj FS, Mandra A, Nguete BU, Likafi T, Kokola G, Tran S, Kennedy JL, Monroe B, Hughes CM, Joseph T, Person MK, Townsend MB, Satheshkumar PS, Kabamba J, Reynolds MG, Rao AK, Kasongo D, Yu PA, Yu Y, Shongo Lushima R, Kaba D, Petersen B, McCollum AM. Safety of MVA-BN vaccine in health-care personnel in DR Congo: a prospective cohort study. Lancet Infect Dis. 2026 Mar 9:S1473-3099(25)00779-0. doi: 10.1016/S1473-3099(25)00779-0. Online ahead of print.

  PMID: 41819117 RESULT

• Petersen BW, Kabamba J, McCollum AM, Lushima RS, Wemakoy EO, Muyembe Tamfum JJ, Nguete B, Hughes CM, Monroe BP, Reynolds MG. Vaccinating against monkeypox in the Democratic Republic of the Congo. Antiviral Res. 2019 Feb;162:171-177. doi: 10.1016/j.antiviral.2018.11.004. Epub 2018 Nov 14.

  PMID: 30445121 RESULT

• Hatmal MM, Al-Hatamleh MAI, Olaimat AN, Ahmad S, Hasan H, Ahmad Suhaimi NA, Albakri KA, Abedalbaset Alzyoud A, Kadir R, Mohamud R. Comprehensive literature review of monkeypox. Emerg Microbes Infect. 2022 Dec;11(1):2600-2631. doi: 10.1080/22221751.2022.2132882.

  PMID: 36263798 DERIVED

MeSH Terms

Conditions

Mpox, Monkeypox; Vaccinia

Interventions

smallpox and monkeypox vaccine modified vaccinia ankara-bavarian nordic

Condition Hierarchy (Ancestors)

Poxviridae Infections; DNA Virus Infections; Virus Diseases; Infections; Primate Diseases; Animal Diseases; Rodent Diseases

Study Officials

• Faisal Minhaj, Pharm.D., MPH, DABAT

  Centers for Disease Control and Prevention

  PRINCIPAL INVESTIGATOR

• Kinkodi Didine Kaba, MD, PhD

  DRC

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: SEQUENTIAL
• Sponsor Type: FED
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 7, 2016
• First Posted: November 30, 2016
• Study Start: February 23, 2017
• Primary Completion: October 31, 2025
• Study Completion: October 31, 2025
• Last Updated: April 23, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

DE (1)