Do We Have a Head Start in Vaccine Production?

If we identify the spill over bad guys before they spill over, don't we get a huge head start on creating vaccines and therapes to counteract that's spilled over pandemic? Don't we have a great potential to really mitigate an awful lot of deaths. In order to have a head start in vaccine production, you need to be able to establish whether it works. We weren't willing to do that even for covid until well over a year into the pandemic. Would we really be willing to do it for a virus that was isolated from animals and might never actually infect a human, or certainly ever take off as a pandemic? What if we discover a couple dozen viruses? Are