Which do you worry about more: the flu or coronavirus? At least from what health officials are saying, the flu has a low mortality rate (the likelihood of dying), but affects so many people that hundreds of thousands die from it each year. That’s why there’s such an emphasis on flu vaccines. Coronavirus seems to have a low mortality rate, but it spreads faster than other viruses like MERS and SARS. One of the worries about pandemics is Nature’s ability to mutate and evolve into threats for which we don’t have defenses. That’s why there’s a great worry every time something like Ebola arises. Will this be the one is lethal and gets out of control? A century ago, diseases were limited by geography. Now, they catch rides around the planet in less than a day. Coronavirus is an unknown, and we worry about unknowns. Pandemics are reminders that we haven’t conquered Nature. We’re getting better, but we are far from perfect and don’t know everything. Is this just practice, or is it the real thing? We don’t know.