Smallpox and Monkeypox Vaccine
Jynneos is a non-replicating viral vaccine approved for prevention of smallpox and monkeypox disease in adults 18 years and older at high risk for infection. It is particularly valuable for individuals who cannot receive traditional replicating smallpox vaccines, including those with compromised immune systems. The vaccine is administered as a two-dose series given four weeks apart.
Jynneos is a smallpox and monkeypox vaccine for adults at high risk, safe for immunocompromised individuals.
Key facts at a glance
- RxNorm
- 2464828
- Generic
- Jynneos
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Jynneos is indicated for active immunization against smallpox and monkeypox (mpox) disease in adults 18 years of age and older who are at high risk for infection. It was initially approved for smallpox prevention and received expanded FDA authorization for monkeypox prevention during the 2022 outbreak.
Jynneos is a Modified Vaccinia Ankara (MVA) vaccine that uses a non-replicating orthopoxvirus vector. Unlike traditional smallpox vaccines, the MVA virus used in Jynneos cannot replicate efficiently in human cells, making it safer for immunocompromised individuals while still stimulating an immune response against orthopoxviruses.
Common side effects include injection site reactions, muscle pain, headache, and fatigue. As a non-replicating vaccine, it can be safely used in immunocompromised patients who would typically be contraindicated for replicating smallpox vaccines. It requires two doses for full protection. Effectiveness against monkeypox when administered after known exposure has not been fully established.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy