The current coronavirus disease [may] be a once-in-a-century evidence fiasco. At a time when everyone needs better information ... no countries have reliable data. This evidence fiasco creates tremendous uncertainty. Draconian countermeasures have been adopted in many countries. The data collected so far on how many people are infected and how the epidemic is evolving are utterly unreliable. Given the limited testing to date ... we don't know if we are failing to capture infections by a factor of three or 300. Reported case fatality rates, like the official 3.4% rate from the [WHO], cause horror - and are meaningless. Patients who have been tested ... are disproportionately those with severe symptoms and bad outcomes. The Diamond Princess cruise ship [had a] case fatality rate [of] 1.0%, but this was a largely elderly population. Projecting the Diamond Princess mortality rate onto the age structure of the U.S. population, the death rate among people infected with Covid-19 would be 0.125%. But since this estimate is based on extremely thin data ... the real death rate could stretch from five times lower (0.025%) to five times higher (0.625%). A population-wide case fatality rate of 0.05% is lower than seasonal influenza. If that is the true rate, locking down the world with potentially tremendous social and financial consequences may be totally irrational. In the absence of data, prepare-for-the-worst reasoning leads to extreme measures of social distancing and lockdowns. Unfortunately, we do not know if these measures work. With lockdowns of months, if not years, life largely stops, short-term and long-term consequences are entirely unknown, and billions, not just millions, of lives may be eventually at stake.