Chasing the ghost of infection past: identifying thresholds of change during the COVID-19 infection in Spain

Luis Santamaria; Joaquin Hortal

With hindsight, it is clear that issuing strong social-distancing measures earlier would have increased their effectiveness, thereby saving more lives and reducing the collapse of the Spanish health system (see e.g. the SIR-based simulations of Casares & Kahn 2020). Our analyses evidence, however, that the responses of the population, media and authorities was slowed down by the perceptual trap created by the prolonged infection-to-detection and infection-to-death lags. It is somehow ironic that the rapid increase in the infections during the last weeks of february (described in phase 1) was only perceivable two weeks later -and, while the increments in number of cases and deaths were attributed to concurrent events that were most likely unrelated, they triggered a swift response precisely at a moment when early containment measures were already starting to work. Similarly, the results of early containment measures were perceived two weeks later, and attributed to a direct consequence of the national lockdown. Fortunately, expert advice to the government was aware of this perceptual trap and insisted on the necessity of stronger social-distancing measures -which have been narrowly sufficient, to date, to reach the objective of flattening the curves.