Projections of epidemic transmission and estimation of vaccination impact during an ongoing Ebola virus disease outbreak in Northeastern Democratic Republic of Congo, as of Feb. 25, 2019

Worden, Lee; Wannier, Rae; Hoff, Nicole A.; Musene, Kamy; Selo, Bernice; Mossoko, Mathias; Okitolonda-Wemakoy, Emile; Muyembe Tamfum, Jean Jacques; Rutherford, George W.; Lietman, Thomas M.; Rimoin, Anne W.; Porco, Travis C.; Kelly, J. Daniel

Gott's rule [39] , presented initially as reflecting a "Copernican" principle with respect to time, assumed that ones observation of the age of a phenomenon occurred at a random time during its lifetime. Gott applied this principle in a variety of settings, including the lifetime of Broadway shows, the Berlin Wall, and of the human race [39, 40] . Critics suggest that Gott's rule gives misleading predictions when the phenomenon in question exhibits known time scales, such as in prediction of human lifetimes [40, 41] . Gott's rule has not been validated for epidemics, and in this case, is based on an assumption that the current case count in an epidemic occurs at a random point in its progression. For an easily detected but uncontrollable supercritical epidemic, we would expect forecasts based on the first reports to underestimate the final size. For an easily controlled epidemic, forecasts would more likely be too pessimistic, since control measures would (by assumption) swiftly end the epidemic after recognition. Our application of the rule is intended to serve as a null hypothesis-like comparator for the other methods.