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

Luis Santamaria; Joaquin Hortal

Official data on the (i) cumulative number of cases, and (iii) cumulative number of deaths were obtained from the daily Covid reports of the Spanish Ministry of Health, as compiled by the Worldometer Coronavirus data service (for national data) and the Covid data service of eldiario.es (for regional data). Data were extracted at two levels of aggregation, for Spain as a whole country, and for Madrid Autonomous Region (i.e. Comunidad Autónoma de Madrid). For the analyses we included data from the first day in which at least 10 cases or at least 1 death were measured; and extended the analyses to 22-24 days after the onset of social-distancing measures on 13-15/3/20, a period doubling the average infection-to-detection time (10.1 days; see next section), and equaling the average infection-to-death time (21 days; see next section).