Imvanex

Imvanex is a vaccine developed by Bavarian Nordic for protection against orthopoxviruses, marketed in the European Union and other regions for smallpox and mpox (monkeypox). It uses a non-replicating recombinant Modified Vaccinia Ankara virus (MVA-BN) to stimulate humoral and cellular immunity without causing active vaccinia infection. In some markets, the same product is sold under the name Jynneos.

Indications: In the EU, Imvanex is approved for active immunization against smallpox in adults at risk of exposure, and for prophylaxis against mpox in adults at risk or after exposure, in accordance with local guidelines.

Mechanism: MVA-BN is highly attenuated and replication-deficient in mammalian cells, eliciting immune responses (neutralizing antibodies and T cells) against orthopoxviruses, while posing a lower risk of disease than replication-competent vaccines.

Administration and dosage: The standard regimen consists of two intramuscular injections of 0.5 mL each, given several weeks apart (commonly 4 weeks in regulatory guidance). Additional or booster doses may be recommended for ongoing risk.

Safety and precautions: The vaccine is generally well tolerated. Common adverse events include injection-site reactions, headache, myalgia, and fatigue. Contraindications include severe allergic reactions to a previous dose or components; use during pregnancy or in certain immunocompromised individuals should follow local guidance.

Regulatory status and handling: Imvanex is manufactured by Bavarian Nordic and approved by the European Medicines Agency for smallpox and mpox in adults. It is supplied in multi-dose vials, stored at 2–8°C, and used before expiration; reconstituted doses have limited stability. The product is marketed in other regions under the name Jynneos.