Cholera Shield Engineered Spores for Rapid Cholera Protection **A Engineering SuperBugs for Good! | HTGAA 2026 | Fiona Connolly **
Overview. Cholera kills more than 100,000 people a year, almost entirely in disasters and refugee settings where oral cholera vaccines arrive at least two weeks too late. Cholera Shield engineers Bacillus subtilis 168 to display a bivalent anti-cholera-toxin VHH nanobody — BL3.2 from Petersson et al. 2025 Nature Communications — on the spore coat via a CotB C-terminal fusion. Each spore behaves as a luminal molecular sponge: it transits the stomach intact, reaches the small intestine, and captures cholera toxin (CT) at the GM₁-binding face before the toxin can dock on enterocytes. The product is a foil sachet — under $0.10 per dose, two-plus years stable at ambient temperature, self-administered in any liquid, pre-distributable into emergency stockpiles, deployable within hours of risk onset. The twelve-week proof-of-concept builds and validates the strain through three orthogonal readouts (display, accessibility, neutralisation) at three GO/NO-GO gates.