Last reviewed 2026-05-13 · How we verify

JYNNEOS (Liquid Formulation)

Centers for Disease Control and Prevention · Phase 3 active Biologic

JYNNEOS (Liquid Formulation) is a Live attenuated viral vaccine Biologic drug developed by Centers for Disease Control and Prevention. It is currently in Phase 3 development for Prevention of monkeypox (mpox) in adults at risk of exposure, Prevention of smallpox in at-risk populations. Also known as: Modified Vaccinia Ankara (MVA), MVA-BN, IMVAMUNE, IMVANEX.

JYNNEOS is a live attenuated vaccinia virus vaccine that stimulates immune responses against orthopoxviruses, including monkeypox and smallpox.

JYNNEOS is a live attenuated vaccinia virus vaccine that stimulates immune responses against orthopoxviruses, including monkeypox and smallpox. Used for Prevention of monkeypox (mpox) in adults at risk of exposure, Prevention of smallpox in at-risk populations.

Likelihood of approval

59.3% vs 58.3% industry baseline

If approved by FDA: likely 2028–2030

Steps remaining: NDA/BLA submission

Confidence: High

Why this estimate

Baseline phase 3 → approval rate +58.3pp
Industry-wide phase 3 drugs reach approval ~58.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
Immunology slight uplift +1.0pp
Mature endpoint landscape (ACR, DAS28, PASI) makes immunology approvals slightly more predictable.

Predicted approval windows by jurisdiction (conditional on FDA approval)

Regulator	Country	Likely year	Lag vs FDA
FDA	US	2028–2030	—
EMA	EU	2029–2031	+0.7 yr
MHRA	GB	2029–2031	+0.7 yr
Health Canada	CA	2029–2032	+0.9 yr
TGA	AU	2029–2032	+1.2 yr
PMDA	JP	2029–2032	+1.5 yr
NMPA	CN	2030–2033	+2.3 yr
MFDS	KR	2029–2032	+1.4 yr
CDSCO	IN	2029–2033	+1.8 yr
ANVISA	BR	2030–2033	+2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic name	JYNNEOS (Liquid Formulation)
Also known as	Modified Vaccinia Ankara (MVA), MVA-BN, IMVAMUNE, IMVANEX
Sponsor	Centers for Disease Control and Prevention
Drug class	Live attenuated viral vaccine
Target	Orthopoxvirus antigens (vaccinia virus envelope and core proteins)
Modality	Biologic
Therapeutic area	Immunology / Infectious Disease
Phase	Phase 3

Mechanism of action

The vaccine contains a modified vaccinia Ankara (MVA) virus strain that replicates poorly in human cells but triggers both cellular and humoral immune responses. This primes the immune system to recognize and respond to orthopoxvirus antigens, providing protection against monkeypox and smallpox infection through antibody and T-cell mediated immunity.

Approved indications

Prevention of monkeypox (mpox) in adults at risk of exposure
Prevention of smallpox in at-risk populations

Common side effects

Injection site erythema
Injection site swelling
Myalgia
Fatigue
Headache
Fever

Key clinical trials

JYNNEOS Smallpox Vaccine in Adult Healthcare Personnel at Risk for Mpox in the Democratic Republic of the Congo (PHASE3)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Source	Used for
ClinicalTrials.gov	Trial enrolment, design, endpoints, results

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

JYNNEOS (Liquid Formulation) CI brief — competitive landscape report
JYNNEOS (Liquid Formulation) updates RSS · CI watch RSS
Centers for Disease Control and Prevention portfolio CI

Frequently asked questions about JYNNEOS (Liquid Formulation)

What is JYNNEOS (Liquid Formulation)?

JYNNEOS (Liquid Formulation) is a Live attenuated viral vaccine drug developed by Centers for Disease Control and Prevention, indicated for Prevention of monkeypox (mpox) in adults at risk of exposure, Prevention of smallpox in at-risk populations.

How does JYNNEOS (Liquid Formulation) work?

JYNNEOS is a live attenuated vaccinia virus vaccine that stimulates immune responses against orthopoxviruses, including monkeypox and smallpox.

What is JYNNEOS (Liquid Formulation) used for?

JYNNEOS (Liquid Formulation) is indicated for Prevention of monkeypox (mpox) in adults at risk of exposure, Prevention of smallpox in at-risk populations.

Who makes JYNNEOS (Liquid Formulation)?

JYNNEOS (Liquid Formulation) is developed by Centers for Disease Control and Prevention (see full Centers for Disease Control and Prevention pipeline at /company/centers-for-disease-control-and-prevention).

Is JYNNEOS (Liquid Formulation) also known as anything else?

JYNNEOS (Liquid Formulation) is also known as Modified Vaccinia Ankara (MVA), MVA-BN, IMVAMUNE, IMVANEX.

What drug class is JYNNEOS (Liquid Formulation) in?

JYNNEOS (Liquid Formulation) belongs to the Live attenuated viral vaccine class. See all Live attenuated viral vaccine drugs at /class/live-attenuated-viral-vaccine.

What development phase is JYNNEOS (Liquid Formulation) in?

JYNNEOS (Liquid Formulation) is in Phase 3.

What are the side effects of JYNNEOS (Liquid Formulation)?

Common side effects of JYNNEOS (Liquid Formulation) include Injection site erythema, Injection site swelling, Myalgia, Fatigue, Headache, Fever.

What does JYNNEOS (Liquid Formulation) target?

JYNNEOS (Liquid Formulation) targets Orthopoxvirus antigens (vaccinia virus envelope and core proteins) and is a Live attenuated viral vaccine.

Drug class: All Live attenuated viral vaccine drugs
Target: All drugs targeting Orthopoxvirus antigens (vaccinia virus envelope and core proteins)
Manufacturer: Centers for Disease Control and Prevention — full pipeline
Therapeutic area: All drugs in Immunology / Infectious Disease
Indication: Drugs for Prevention of monkeypox (mpox) in adults at risk of exposure
Indication: Drugs for Prevention of smallpox in at-risk populations
Also known as: Modified Vaccinia Ankara (MVA), MVA-BN, IMVAMUNE, IMVANEX

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing