The San Diego community exchange is a model of what a CIE can be, and it has sparked a spread of the concept. It coordinates and provides tools and mentorship for a national network of more than 30 other places building their own exchanges. One effort it’s assisting is in Chicago, where an exchange is being built by the Illinois Public Health Institute. As in San Diego, Chicago’s exchange is initially focusing on people experiencing housing insecurity, but IPHI is building the system so it can include other populations.