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InVitria Publishes Review on Vaccine Formulation for Bundibugyo Ebolavirus
Published on 24 September 2026
What the DRC outbreak means for rVSV vaccine candidates now in development
Scott E. Deeter, Chief Executive Officer, and Mark Stathos, Ph.D., Director of Cell Biology, have published a scientific review examining what it will take to move an rVSV-vectored Bundibugyo ebolavirus vaccine from preclinical proof of concept into a product that survives manufacture, freezing, thaw, and delivery in the field.
The review arrives during an urgent moment. Bundibugyo ebolavirus emerged in Ituri Province in May 2026 and has become the largest Ebola outbreak ever recorded in the Democratic Republic of the Congo, with WHO declaring a Public Health Emergency of International Concern. No licensed vaccine protects against Bundibugyo virus, and WHO concluded in August 2026 that evidence for ERVEBO® cross-protection is inconclusive. CEPI has fast-tracked three Bundibugyo vaccine candidates, two of them rVSV-vectored and both descended from the platform behind ERVEBO®.
That lineage is where formulation science becomes decisive. An rVSV particle is a fragile, host-cell-derived lipid bilayer studded with glycoprotein trimers — vulnerable to shear, to adsorption onto process membranes, and to freeze-induced inactivation. The review assembles the published and internal evidence that recombinant human serum albumin addresses these failure modes directly, including Merck’s finding that formulating with recombinant albumin and pre-flushing the membrane raised sterile filtration step yield from 42% to 74% by infectious potency, and InVitria’s own lentiviral vector data showing comparable gains across depth filtration and tangential flow filtration.
Where albumin enters the process is a process-design decision, not only a final-formulation one.
ERVEBO® is formulated with 2.5 mg/mL of InVitria’s recombinant human serum albumin in 10 mM tromethamine — the only stabilizing excipient in the licensed product, and the first recombinant albumin approved as an excipient in an injectable biologic of any type. The authors argue that the excipient choices being made today for the next generation of filovirus vaccines will set the limit on how far into the field a licensed product can travel.
Deeter SE, Stathos M. Translating pre-clinical rVSV success into field-ready vaccines for Bundibugyo ebolavirus: lessons from ERVEBO® and recombinant albumin. Junction City, KS: InVitria, Inc.; 2026. This is a scientific review and has not undergone formal journal peer review. Both authors are employees of InVitria, Inc., which manufactures Exbumin® and Optibumin® 25.