What Characteristics Do You Think We Need in New Vaccines?

The vaccines we have are pretty good, but they're not as good as they once were. We'd love to get back to having vaccines that could do what our original vaccines did. Will that take better matching of vaccines to circulating strains? Or will that take a new technology, or a new way of delivering an gin? I'm not sure, but i think all those things are in the works, and they're going to be very important to explore.