Post-exposure vaccination with IMVAMUNE protects against lethal poxvirus infection
In studies with Bavarian Nordic's new and innovative third-generation smallpox vaccine, IMVAMUNE®, scientists from Bavarian Nordic have for the first time demonstrated a therapeutic effect of a smallpox vaccine, days after infection. With the current available first- and second-generation smallpox vaccines no evidence of a therapeutic effect has ever been shown in animal models. This discovery was recently published in the Journal of Clinical Investigation.
The scientific paper "Survival of lethal poxvirus infection in mice depends on TLR9 and therapeutic vaccination provides protection" shows that a single vaccination of IMVAMUNE® could protect a variety of immune suppressed animals on the same day as a lethal challenge with Ectromelia virus; a natural poxvirus infection of mice that closely models smallpox infection in humans. Some of these mice were so immune suppressed that vaccination with a traditional smallpox vaccine (e.g. Dryvax®) led to the death of the animals prior to any challenge with Ectromelia. Not only was IMVAMUNE® therefore shown to be safer than traditional smallpox vaccines, but a single vaccination with IMVAMUNE® given up to 3 days post the lethal challenge with Ectromelia protected the mice. This is the first therapeutic or post-exposure protection, demonstrated for a smallpox vaccine in a relevant animal model.
These data follow Bavarian Nordic's previous observations that IMVAMUNE® induced a faster protective immune response compared to traditional smallpox vaccines. Moreover, IMVAMUNE® is currently in phase two clinical studies and so far more than 1,600 subjects have been vaccinated. IMVAMUNE® has been shown to be well tolerated even in subjects not considered candidates to receive the current first- and second-generation vaccines (e.g. HIV and Atopic Dermatitis patients).
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